After Put the Thing on the Thing

You are in control of Unikitty, Batman, Benny, and Wyldstyle. Head left and hop on the bars, then destroy the rainbow blocks to reveal rainbow LEGO pieces. Build them into a catapult, then step on it to reach the upper ledge. Activate the console to reveal a box on the ground. Grapple onto that to reveal a terminal. Hack it to open the door. Walk through it to start the next level.