Rainbow Dash runs a mutant gauntlet.
The X-Men have kidnapped Scootaloo, Rainbow's adopted younger sister, for completely convoluted and irrational reasons I am too lazy to explain and so they will be handwaved. The result is that Rainbow Dash is in Serious Business mode and will not suffer from CIS during this gauntlet, she's out to win from the outset and rescue her Crippled Midget Chikun, because Loyalty. She is not healed between rounds, but she is determined.
Rainbow knows exactly where Scootaloo is because Pinkie Pie told her.
The X-Men and assorted mutants are divided up, because they're not expecting Rainbow. Victory is by any means available. She just needs to get past them to get to the next fight.
Round one: Wolverine and Deadpool are playing Basketball outside when she shows up. Because reasons. She needs a key from one of them to get to the next fight.
Round two: She unlocks the door to a closed off stadium where Gambit and Quicksilver are playing baseball. Why? I have no idea, but Gambit is cheating. In order to stop her they have to prevent her from getting through the door on the opposite side of the stadium.
Round three: The door leads to an underground warehouse where Cyclops and Jubilee are cleaning their Fancy Jet. Inside the Fancy Jet is a sheet of paper with the password to a teleporter. Scott has the key to the Fancy Jet.
Round four: On the other side of the teleporter she finally gets to Scootaloo, who is in a cage, being defended by Colossus. (not Juggerlossus, **** that) In this final round she's willing to go all out, and will fight until she's completely incapacitated, or Scootaloo is rescued.
Rainbow gets all feats from the cartoon and the comicbook, can they stop her?