How to force play an animation for a mob

Hi,

I want to essentially fix a mob's position at a certain position. I want them to play their walk animation but their actual movement will be fixed. Essentially, looking like they are moving in place.

Looking for pointers on the best way to achieve this. The simplest way that I am trying to think of is turning off AI and trying to play the animation, but I can't seem to figure out how animations are actually executed for mobs. 

Thanks