Robots vs. Dragons
From SmashWiki, the Super Smash Bros. wiki
Robots vs. Dragons (known as Robots vs Reptiles in PAL versions of the game) is a co-op event match in Super Smash Bros. for Wii U. Player 1 controls Mega Man while player 2 controls R.O.B.. The players must initially defeat Giant Yoshi, Giant Charizard, and Ridley in a 200 HP battle.
Completing the event within 70 seconds awards a Double-Jump Boost Helmet equipment.