The Tower of Yikk is both a location and a boss in Mario & Luigi: Bowser's Inside Story. Bowser encounters the tower at Blubble Lake, while he is looking for the first Star Cure. He sees a propeller protruding out of the ground, and uses a super-powerful sneeze to activate it. However, the tower comes to life and lands on top of him, forcing the Mario Bros. to activate Bowser's growth abilities for the second time at the Rump Command. Bowser then defeats the tower, doing so by punching it into the lake and then punching it in the head. The tower is then permanently deactivated, meaning that Bowser can now access it. A Save Block and a Shop Block are inside the tower. After an elevator and a hallway, Bowser enters a study. The door then locks behind him, and he meets Yikk. Inside the study there is the Boo-ray Machine, which Bowser uses, making some Boo-like blocks disappear in Energy Hold, allowing the Mario Bros. to go there.
After the events in Energy Hold, in Joint Tower, the Mario bros. make it so that Bowser can use the Body Slam. Bowser Body Slams a large ! Switch on the ground, opening the door.