Koopa Paratroopa Stack
From the Super Mario Wiki
Koopa Paratroopa Stacks are a type of enemy appearing in Paper Mario: Color Splash. A stack of Koopa Paratroopas is formed when multiple Paratroopas group up, forming a stack. They appear only as a 10-Stack, and their health is represented by the number of Partroopas left in the stack. Koopa Paratroopa Stacks appear on the Sunset Express.