From a young age Bobby was raised by his mother, because his father just up and vanished with no notice. He was a pretty normal boy with nothing really noteworthy about his childhood. He's said that his mom had to work two jobs to properly take care of him, so he probably rarely got to spend much time with her and had to accept that early on. This also means that he had to be more self-reliant from a young age. He grew up to love lizards, skateboarding, and graffiti...and to all appearances by the time he had turned twelve, he had already stopped caring that his dad had apparently abandoned him. But in reality he hadn't and likely got defensive if the subject was ever pressed.
His love for lizards was a bit beyond the norm though, as he would go out of his way to take care of them. So naturally when corporate happenings and movie development threatened lizards when he was twelve, he stepped in to protect their rights. He witnessed a movie rehearsal where a lizard was abused on-set, and protested at the premier...as well as drew lizard graffiti on the director's red carpet. He scaled an X off of a building in the name of saving lizards. And when he found an unusual lizard living near his town, he moved into a tree in the same area and lived there for four months to protect its habit. All this was without realizing what he was meddling in, or what it would lead to.
Late one night sometime later, he was kidnapped by his neighbor, Looger. His continued meddling in things had made him stumble onto an alien invasion plot completely without realizing and it was assumed that he must have known something which made him a threat. He woke to find himself strapped to a chair in Looger's basement with the military guy from TV, Captain Bootcamp, ready to interrogate him. In attempting to make him talk, Bootcamp used a strange electrical lizard energy on him, but was soon ordered to shut it off when a portal was opened in the basement as a result. Bobby noticed that just for an instant his own hands became lizard claws, and the residual energy in the room also somehow let him see through the nearby one-way glass to spot Looger and the three people he'd been opposing in the name of lizards...as well as see that they were all lizards themselves. When he expressed his shock, Bootcamp happily gloated that Bobby didn't know the half of it and that they had taken many lizard eggs from Earth to their world and were doing something to them to raise them as super soldiers.
The interrogation might have proceeded properly, but the way Bootcamp sucked up to the concealed Looger had Bobby poking fun at him. Evwntually he lost his temper when Bobby nailed him is the nose unexpectedly with his new lizard tongue catching a fly that had landed there, much to Bobby's disgust. Bootcamp hit him with another blast of the strange energy, and he transformed fully this time. The force of his convulsions snapped his restraints and the portal was reopened, and he dived into it to escape capture, finding himself in an alien world. The strangeness of the entire situation made it hard to take seriously though and he was certain that it was another strange dream brought on by eating chili before bed again.
Exploring the new world, Bobby adjusted to his new form quite well as he waited to wake up, and eventually happened upon another lizard, named Leon...which he found a bit odd as that was his father's name, but didn't think on much because there wasn't a reason to make a connection and Leon didn't know him. Leon had been reading the file Looger's henchmen had made on Bobby, which had been sucked through the portal during the chaos, but soon left when Bobby was determined to keep thinking he was dreaming.
Left alone, he continued to explore, gradually beginning to think that maybe he wasn't dreaming, and eventually came across a large flying lizard unlike anything he'd seen. When he made to approach it, Leon appeared and angrily told Bobby not to even think about stealing the reptile...called a Repbaldactile. A short conversation later, Bobby had to come to terms with the fact that he wasn't dreaming...but he took offense to being told he was a speck of dust in the multiverse and boasted that he could do anything. Leon challenged him to get the lizard egg in the strange incubator in the area and he did so to prove he could...and having realized it was from earth.
When he returned, he found out that Leon was planning to collect all the eggs and send them back to Earth with the help of a portal beacon he knew of. It being his only way home, and completely unwilling to let some strange alien lizard leave with the egg, Bobby insisted on going with him and even offered to help him get the eggs. Realizing he was kind of stuck, Leon agreed, though he'd be making Bobby do all the footwork from then. That settled, they boarded Reppy and flew to the next area.
In the next region, Leon taught him about the little energy balls called Kloakkies, which could be collected from pretty much everything in the world and then converted to enhance his abilities or grant new skills. He also warned him about the bomb-wielding Bakudan and informed him of the fact that he could gain the ability to transform into one by absorbing enough of their energy after defeating them. He did so as he traveled the region, using the bombs to navigate the areas that were largely only passable to Bakudan or by scaling the many stone "walkways" until he found the eggs incubating there.
On the way to the next area, Bobby spotted an egg and had Leon let him off so he could get it. He was confronted by Looger's trio of lackeys who, rather than attack him after a round of banter, let the lizard that hatched from the egg fight him. Bobby defeated the lizard, a giant frilled and tusked monstrosity called the Iguana King, and discovered another egg in a nearby chamber before returning to Leon. When he expressed concern over what the hatched egg had become, Leon told him that Looger was mutating the eggs to hatch into various elite lizard soldiers, which would then be cloned to become an army that could invade every plane of the multiverse including Earth. The portal beacon they needed to send the eggs home and stop Looger was also in Looger's possession and Leon was still working out the details for how to steal it.
The next region saw him getting the Krock transformation on his way to the eggs, as many areas were railways and timed gates he couldn't reach as he was. The region after that required him to collect enough Kloakkies to get the camouflage ability from Reppy, or risk being eaten by Trappers on his way to collect the eggs.
It wasn't until they were passing the cold region that real trouble struck again though. Looger's three henchmen attacked on a Flying Yeti, and Bobby had to take on all three...thankfully one at a time, though having to dodge the Yeti's lethal ice attacks after each Jazz and Rombus were defeated. Once he had also defeated Turbine, the Yeti fled and he found another egg. He also learned that Leon's memory had been wiped by Looger and his henchmen, and that his presence was helping his memory return...but the combination of not thinking on it much and an imminent crash while Leon was distracted kept him from putting the pieces together.
The next world initially forced Bobby to put his life in the "hands" of Reppy, as they were attacked by a barrage of reptilian projectiles and there were no parachutes for him to bail and she was the defense system, but they landed safely and he used his Krock transformation to race for the egg in the area so they could move on. While nothing too threatening for Bobby was found in the next region, the one after that pitted Reppy against a giant flying Rattle Crab and once again meant Bobby had to trust the flying lizard to keep him alive.
After he retrieved that region's egg, he found Leon spacing out again. Leon revealed the knowledge of Bobby's mother's name and told him his father hadn't abandoned him, something Bobby responded to with insults because he still hadn't put the pieces together himself. It turned out that Leon had been a scientist researching the portals and, after creating the portal beacon, had been sucked into this world and captured by Looger...who had tortured him for months to learn how the portal beacon worked before leaving him stranded here with no memory. He was Bobby's father.
Pleased with his full recollection, Leon had promptly hugged Bobby and told him how proud he was of him...something that Bobby took poorly, immediately shoving him away and denying he could be proud of someone he didn't even know. But they both acknowledged this was something that would take some time, and continued on their way.
In the next region, Bobby had to take down a large Doozum alone to gain its transformation and reach the egg hidden there. The following one found him using his camouflage a lot to pass unfriendly plant life and tracking down a dozen Fruzard to get their transformation as he sought more eggs...the smallish sniping lizards appearing in areas small enough to really put his dodging skills to the test.
Bootcamp was the next to confront him, his lizard form a giant fire-breathing sea serpent that Bobby couldn't easily take down head-on. But he managed it with well-timed use of his Fruzard form and his quick reflexes before claiming the egg Bootcamp guarded and moving on to the next place. On the way he attempted to make the first step in reconnecting with Leon by asking him a little about what the Multiverse and portals were, also learning that there was no certainty for what would happen when they passed through theirs again...he shut down any attempts at affection though, but finally did cave in enough to call Leon "Dad".
The next region was a heavily aquatic area, hard to navigate because of the fact that he couldn't swim as he was. Thankfully, there was a convenient solution among the hostile residents and after taking down about half a dozen Swoom, he was able to dive in and more thoroughly search for the eggs in the region. The next area required Reppy to once again clear the skies before landing, and Bobby's use of the Fruzard and his vine-surfing skills to reach the eggs.
With all of the eggs accounted for, Leon flew them to Looger's stronghold to confront him and take back the portal beacon. Portals were easy to come by, but the portal beacon could pinpoint the current location of their portal. They could go home and the return trip would turn them human again. Unfortunately, Looger was expecting them, and caught Bobby and the eggs in a trapdoor. Alone but unwilling to let Looger finish mutating the eggs, Bobby stood and fought him and all the lizards he called in to help. Defeated, Looger fell into his own dungeons as Bobby claimed the portal beacon and returned it to Leon, who was still trying to get inside and very worried for his son.
Leon found their portal, but it was unstable so they had to hurry. As they ran, Bobby dropped an egg without realizing and Leon stopped to retrieve it, throwing it to Bobby with enough force that he was knocked through the portal when he caught it. He arrived safely back in Looger basement on Earth and waited anxiously for Leon to come through the portal...but he didn't make it and the portal closed.
((Canon background ends here. The AU part of his background following this is based on both the secret ending and the explanation for
the Multiverse. The secret ending had dropped him in a merged timeline where Leon had never vanished and so he had grown up with both parents, but both Bobby and Leon clearly remembered the events from Bobby's original timeline. Bobby's also shown to still have his lizard tongue and therefore it's likely that he still has his lizard powers.))
Bobby returned home, not having been gone long enough for his overly busy mother to notice anything unusual and expecting things to be mostly normal now that Looger was gone and the eggs were safe...even though he somehow hadn't been holding a single egg when he'd arrived. But it turned out that he hadn't been returned home at all, instead having appeared on a different version of Earth where superheroes existed and his mom didn't live in the house next door to where he'd been sent...leaving him with nowhere to go and no one to turn to. He didn't have the portal beacon, so even if a portal did appear he had no way of knowing if it would send him home, back to Leon, or somewhere else entirely. He also found out rather quickly that he was not fully normal again either, despite having been returned to his human form.
It started simply with him catching a fly with his lizard tongue even though he was human, much like the first time. Even though it was both disgusting and a painful reminder of his current predicament, it made him wonder enough to eventually try transforming in the same way he had with his transformations, finding that he could change from human to Scaler and from Scaler to any of his other forms...but not from human to the others or vice-versa. His other Scaler powers were also intact, which as much as he was now resenting them could come in handy and so were worth keeping sharp.
Being the stubborn headstrong teen that he was, Bobby decided that he'd just make it on his own. He lived on the streets, earning money by doing the same odd jobs around the neighborhood that were normal for a teenager: mowing lawns, washing cars, walking dogs, raking leaves, shoveling snow, painting fences and walls, and other things like that. He took up residence in an abandoned apartment, living mostly off of instant foods or fast food. When he went out he commonly kept a skateboard and backpack on him...a coat as well in the winter. He also had saved money to buy himself a laptop, but it was only really usable where he could charge the battery. Fun was still had in skateboarding and graffiti when he could afford the spray paint, and he didn't lose his love for lizards, but he added the hobby of turning his adventure into a comic to his list as well.
When he wasn't earning money or just trying to enjoy himself, since he didn't have to worry about school, he would sometimes go someplace secluded where he could practice his powers without drawing attention to himself. As Scaler, he practiced with his claws and tongue, as well as learned to use his camouflage even on walls and ceilings rather than just on the ground...with that camouflage contributing to his ability to avoid being taken by social services. He learned to fight a little in close quarters with his Bakudan form, which had always been rather helpless outside of using the bombs it could create one after the other. He also practiced on the Fruzard's aim and agility, the Krock's speed, the Doozum's accuracy and maneuverability, and even on the Swwom's swimming and ramming attacks.
This went on for about three years before anything happened to disrupt the routine that had become his life. But what happened could be considered a matter of him having been in the right place at the wrong time or maybe in the right place at the right time...or just him being perceptive enough to notice something that had only been there for a moment.
It had just been a day like any other, but he was on his laptop at a cafe and there had been a report regarding a new animal sanctuary that was opening. He'd only really been watching because that had been what was on and it was moderately interesting, but just for a moment he thought he'd caught a glimpse of a Ratos on the background. When he paused and rewound the video, it was indeed a Ratos in the sanctuary and that was enough to send up glaring red flags. He had looked up the location of the sanctuary in South American and flew there as fast as his Doozum form could take him. He wasn't the only one though.
When he arrived, it wasn't quite the situation that he had been worried about, no signs of Looger or his henchmen or any alien lizard technology. Not even that many Ratos in the sanctuary (less than half a dozen that he spotted as he made his way into the main complex) despite them being known to travel in packs. What he did find were for young superheroes also investigating, looking for evidence of genetic experimentation or alien technology: Robin, Beast Boy, Blue Beetle, and Kid Flash. But he didn't get to spy on them long before Blue Beetle notice him despite his camouflage.
Things almost came to a fight, as a blue lizard spying on them when they were here because of lizard-related circumstances didn't look good on his part. But he managed to convince them that he was truly only here to find out why there were Ratos here as well. As it turned out, there was no evidence at all here for anything suspicious even when Robin hacked the computers. The staff running the sanctuary had apparently just stumbled across them and come to the same conclusion that had led Bobby to live in that tree way back before his adventures as Scaler started.
With nothing more to go on, he'd been ready to make the long trip home, but was asked to come with them to share what he knew as well as to have it verified that they could trust him.