O.R.I.G.I.N.A.L.

This is not a monkey or bloon, but some kind of thing that no one has ever thought of. If it appears, it has been thought of, so every time it appears it looks different. It has an HP that was never thought of. It can use every attack that has never been thought of, but as soon as it uses an attack, it has been thought of, so it can only use each attack once.