Banzai Bill Thrill
From the Super Mario Wiki
Banzai Bill Thrill is a first officer command used by Roy in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey. It is Roy's second command, the first being Shell Shock. It costs 7 CP to use. When activated, Roy and Bowser Jr. will ride a Banzai Bill across the battle area three times, damaging all enemy units each time. Roy first uses this attack during his one-on-one battle with Bowser Jr.