When putting a player skull on a Villager with /replaceitem, the game's graphics are VERY glitchy. All signs, chests, skulls, dropped items, inventory items, etc. are rendered in the wrong spot. Also, when attacking a villager with a skull,my screen turned black, but still functioned properly. This may be a bug with my graphics card, but something like this has only happened once before. (http://imgur.com/a/nc3wX but this was 9 months ago during a buggy snapshot)

Screenshots:
1: The black screen
2: Buggy signs and skulls
3: More buggy signs and skulls
4: Buggy inventory
5: Floating dropped diamond sword (not actually there)