After the story, there's a Sentinel that lands in the X-men school courtyard. Fly over there as Iron Man Mark 42, hit the silver section on his chest, then heat beam the golden section underneath. Now switch to a muscle character like The Hulk or The Thing and hold
to rip up a piece of earth. Throw it at the last section and Sentinel will be defeated, leaving the Colossus token behind.
Buy him, then make the two on screen characters Colossus and Wolverine. Push towards Wolverine and
at the same time and Colossus should pick him up and throw him. Achievement unlocks shortly thereafter.