From SmashWiki, the Super Smash Bros. wiki
Robotic Rampage is a single-player event match in Super Smash Bros. for Wii U. The player controls R.O.B., helped by 2 other R.O.B.s, must defeat a giant metal R.O.B.. It is similar to Brawl's Event 15: The Hammer of the King, where the player joins forces with two other characters to defeat a giant metal enemy.
Clearing the event within 70 seconds awards an Item-Hurler Block equipment.