Ethan

Yeah, Hulk wins without a problem. The Beast couldn't hurt him.

unfortunately for Robin he doesn't know anything about Saiyans. If I were writing this story, Robin would use his stealth to hide and try to figure out what is going on. If he can deduce that the Joker is involved he may be able to free the young Saiyan and save the day. However, he doesn't know this. All he knows is he is up against another energy producing villain (quite powerful at that). He'd probably try to take him down with a sneak attack. Most energy producers are not usually Martial Artist who are Super strong and nigh invulnerable as well. But Trunks is. I see this ending badly for Robin. Unless of course he does stay out of sight or fakes his death. something like that. Vote: Trunks

Percy is a kid...would he kill Vader if he had the chance? Who wins initiative? If Vader does, it could be over in a flash of his light saber, taking off the boys head...however, Vader's not like that. If he doesn't know the kids power, he would more likely gloat about how useless it was for him to resist...etc. If Percy jumps in the water, it sounds like he's safe there. Perhaps Vader leaves, he has no problem with fleeing if he sees the power this boy can unleash and doesn't see a way to beat him. (of course that's a win for Percy I guess).

Physically, both are probably pretty equal... The 50 hippies would be standing together, and since they are acid tripping (but not scared) would really fight back. The Fanboys would each want to get inside the con but wouldn't be doing it as a team effort. Some of the fan boys may make it inside but at the cost of their slower comrades. Hippies win!

Well, Finn and Fionna are alternate dimension versions of themselves...so, they are very equal when it comes to skill and abilities...all the way around. So, it comes down to a boy fighting a girl, I guess. Finn wins.