The Monkey Ace is a moving unit operated by a monkey that debuted in Bloons Tower Defense 4. It also appears in its Expansion, Bloons Tower Defense 5 and Bloons 2. In BTD4 and BTD5, it costs $765 on Easy, $900 on Medium and $970 on Hard. It will automatically fire at the Bloons. When the player places it on the screen, it will automatically fly in a figure eight form, and has infinite Range. However, in BTD5, the player can switch the Monkey Ace's route between an 8 shape, an ∞ (infinity symbol) shape and an O shape. The O shape is usually most efficient, as the monkey ace does not move out of the screen (unless you place it near a corner).