I found a bug in the minecraft inventory, when you put in this command:
/replaceitem entity @p slot.armor.head skull 1 3 {ench:[

],display:

,SkullOwner:}
It makes your inventory go wierd/stuff up *Until* you take the skull off.
**Edit**
It also stuffs up your shadow by putting it your head and also the environment around you and makes anything like chests and banners move behind you. This only happens if they are in the area.