Trash was another one I made up way, way back in the day, probably around 7th grade. Now, it seems he's a Hulk spin-off, but that's not essentially true. I never read Hulk comics, and truth be told I knew very little about the Hulk. He's green not because of the Hulk, but because I gave him a face like a Ninja Turtle (hence him not having a nose, and sometimes I draw his mouth in an almost rounded beak-like fashion). I think when I created Trash I was reading WildC.A.T.S., which was a pretty shitty comic in retrospect, but I ingested anything and everything Jim Lee had a hand in, so I guess it's fair to say I wanted my own "Maul" character. Just about every super-group has the big muscle guy, and more often than not he's the dumbest one on the team (though Maul and Beast are exceptions). I decided to make Trash so dumb, he basically had the brain of a child, as if the process that changed him into Trash inadvertently destroyed his mind. Not a very original concept, I know. Really, nothing about Trash is all that original, but that doesn't mean he's any less fun to draw and write for.
I'd sometimes draw him with two arms, and sometimes four. I couldn't decide which look for him I liked better, so I gave him the ability to grow extra arms.
Trash does have a fairly scripted origin that I won't be changing much for Super U., but I can't tell you much about it, because that would ruin the surprise.