When I was brainstorming fast running type animals for this game idea, I knew I had to put in a nasty baboony apemonkey in there. Every limb extension seems to contain the intent to kill. I reworked his face a bunch of times combining different features of different baboons and mandrills.
Looks properly fearsome and dangerous. Animals like me, and I like most of them back, but I was always wary of Monkeys and Apes. Baboons and Chimpanzees especially, they can be extremely aggressive and they have the intelligence to be cruel, too. Reportedly they often go for the eyes and nose when attacking humans. Yikes.