Ultimate Spidermonkey is the evolved form of Spidermonkey.
Ultimate Spidermonkey has a large gorilla body with purple skin and dark purple fur. Ultimate Spidermonkey has lost Spidermonkey's tail and extra pair of arms, but they get replaced with two pairs of spider legs that can fold into his waist and the ability to shoot web out of his mouth. Ultimate Spidermonkey wears the evolved Ultimatrix symbol on his chest.
Ultimate Spidermonkey much is stronger than Spidermonkey. By splitting his lower jaw in two halves, he can shoot webs from his mouth, much more than Spidermonkey can shoot from his tail. He still has high agility due to the spider legs on his back. He can also fold them into his sides. He can use the tips of his spider legs as a spear to stab as they're extremely sharp. His webbing is also stronger than Spidermonkey's. He can also climb walls to the extend of standing upside-down on either his spider legs or his other feet.
- Ultimate Spidermonkey is the first Ultimate to be used in Ultimate Alien.
- He is the third Ultimate Form to appear in general.
- In Reflected Glory, Ultimate Spidermonkey's jaw kept splitting whenever he spoke. This didn't happen in any other appearance.
- Ultimate Spidermonkey cannot survive in space, unlike some of Ben's other alien forms.