So I used the Fox NPC by justinmcintyre911 to make a wolf NPC that I could use in my game. All I did after changing the colors and scaling it up, was switch out the NPCAIClient and NPCAttackClient with the same scripts from the RPG Skeleton Swordsman in the NPC AI Kit by standardcombo. Then reattached the roots and stuff. I cleared all the errors, but still get this one, and I cannot attack the wolf. Any suggestions? Ive spent like 2 hours looking for an answer, and have come up with nothing lol Thanks y'all!
Did you rename the wolf's mesh "AnimatedMesh"? I ask this because the MESH variable is determined by the code: local MESH = script.parent:FindDescendantByType("AnimatedMesh")
If no object named "AnimatedMesh" is present, MESH will be nil and an error will be thrown.
I did just try to rename it "AnimatedMesh" and made sure that was all correct, but it is still throwing up the error. Its the same mesh used by the fox mentioned above.
Oh, my bad, renaming it would change nothing as the search function is FindDescendantByType, I was on autopilot and thought the code was FindDescendantByName 
. Is the "AnimatedMeshCostume" script within a client context? Is the AnimatedMesh object within the same client context as the "AniamtedMeshCostume" script? Also the "Fox" animated mesh does not have the stance "1hand_melee_ready" which is on line 24 (MESH.animationStance = "1hand_melee_idle_ready" ) you will need to change the stance name to one that the fox animated mesh has.
There might be the issue. There is the AnimController and the animated mesh, but there is not an AnimatedMeshCostume script in there. Am I right in that thinking?
I believe your "AnimController" is a renamed "AnimatedMeshCostume" script.
I'm not sure on that one because line 24 in that script is nothing like the error.
That is also part of my issue in fixing this. I checked every script in the wolf and that is only one with anything on line 24. The rest are blank on that line.
So I was able to fix the damage issue by removing the part from "else" to "end" there with the "unarmed_claw"; however this error is still popping up. Hmmm
I fixed that error! It turns out it had nothing to do with the fox and everything to do with an npc I was making in the same project. Lol I am sorry for wasting your time.
However, any quick idea on why the fox spawns and animates halfway through the floor? Lol
Also thanks a ton. Im new to coding and doing all of this, but im having a blast learning.