If you are in third person mode and have used an invisibility potion, your characters animations are controlled by other players on the server you're currently logged in to.

In multiplayer:

• Head movement while wearing a mob head
• Item in hand - Attacking does not cause the item in hand to swing.

In singleplayer:

• Character always has the head slightly downwards to the left if wearing a mob head.
• Item in hand does not swing when it should. I.E. when attacking.

Steps to reproduce
1. Simply enter third person mode using the [F5]-key. Front or back works.
2. Use an invisibility potion (drink or splash).
3. Try swinging, and have another player do the same.
4. Also have another player looking around or just walking around.