For Avenger OCs

You and the team are on a mission when a small device in an apposing agents hand went off in the building like a bomb, throwing everyone backwards. You and (OC or Cannon Character of your choice) where thrown back into the wall, draining every superpowered person in the room of their abilities.

For Villain OCs

You've got the Avengers or X-Men right where you want them. They've all been hit by a powerful blast leaving them without their mutant abilities.

For X-Men OCs

You and the team were going to locate a mutant when going to approach them a strange EMP like pulse went off and removed your abilities.