Turtle (Wario Land series)
From the Super Mario Wiki
Turtles are helpful allies that appear in Wario Land II. They can be found near water at some places. If Wario jumps on them, they will help Wario by carrying him over strong currents. However, they will not stop themselves if Wario is not quick enough to keep up with the turtles. If their way is blocked by a wall or if they have disappeared from the screen, they will return to the place where Wario found them.
A single turtle that acts similar is also found in Wario Land 3 in the room of the boss Muddee. When the turtle spots the boss, it will get frightened and retreat afterwards. If Wario manages to defeat Muddee, the turtle will reappear and continue its way along. Another turtle, this one bipedal, appears as the goalkeeper in the arena of the boss Shoot. This one takes on a more antagonistic role, attempting to prevent Wario from scoring. The battle can be eased by attacking it, which knocks it into its shell, giving more room for Wario to knock Shoot into the net. However, after about 4 seconds, the turtle will right itself. Once Shoot is defeated, the turtle will spin around in its shell and be usable as a hovering platform to attain the Blue Music Box.