From the Super Mario Wiki
Lollygagging Larry is a level in Bowser's Castle (East) in the Bowser Jr.'s Journey mode of Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey.
This level has three battles. The first battle has two green Koopa Paratroopas, five Boos, one red Shy Guy, and a Boo captain. The second battle involves five green Koopa Paratroopas, two red Shy Guys, a Boo first officer, and a Boo captain. The third and final battle contains two Boos, four green Koopa Paratroopas, two Shy Guys, and Larry as the captain. In the third battle, Larry can use the move Snack Time to heal himself or his allies. After the battle, Bowser Jr. teases Larry knowing that he was more stronger than him. Larry felt Bowser Jr. was persistently strong enough to take him down. Roy, fed up, tells Larry that he should show more respect from him. After this, Larry joins Bowser Jr.'s squad.