Sentinel

Sentinels are small flying creatures that act as a second guard in Tubba Blubba's Castle. In Paper Mario, you can't fight them, and they can't hurt you. When Mario gets too close, they will flash and try to grab him. Use Bow's disappear move to confuse them. If one catches you, it will throw Mario and his party out of the castle.

When Tubba Blubba chases Mario and crashes the bridges above the main room, the sentinels will get crushed by the debris. They leave after the chapter is over.