A Cosmic Paratroopa is a version of a Koopa Paratroopa. They first appeared in Super Mario Sunshine 101 in Outer Space, World 3. He also appeared in Mario and Sonic Party
In battle, a Cosmic Paratroopa can make more Cosmic Paratroopas or Cosmic Troopas appear on-screen. The summoned Paratroopas and Troopas can also summon additional forces. If you do not attack them quickly, the screen will quickly fill up. You have to defeat all of the Cosmic Paratroopas and Cosmic Troopas to continue.
Cosmic Paratroopas can work together and form a Koopa Stack. The top of the Koopa Stack throws additional Cosmic Paratroopas at Mario and his helpers. They can also attack by freezing you.