why wont playing an animation on an npc work?

im trying to play an animation on an npc and it wont work i have the right setup and everything: https://gyazo.com/fef217da37511e8e9c81445804e3e0a2 but it wont work

local animController = Instance.new("AnimationController")
local animTrack = animController:LoadAnimation(animation)
animController.AnimationId = 337868735 
animTrack:Play()

Despite what the wiki says, Load the animation into a humanoid. That seemed to work for me.