Trampoline Shy Guy
From the Super Mario Wiki
Trampoline Shy Guys are a varient of Shy Guys that appear in Paper Mario: Color Splash, where they are only found in The Emerald Circus. They are a stack of fifteen green Shy Guys that bounce on a trampoline. Due to them jumping on a trampoline, all Jump attacks will miss. Mario must use his hammer on the trampoline so the Trampoline Shy Guys fall down, which allows them to be jumped on. If the trampoline is attacked again while they are down, they will get back up. Trampoline Shy Guys attack by jumping off of their trampoline onto Mario. Upon defeat, the trampoline will be left on the stage, allowing Mario to reach Lemmy Koopa.