Heads

Logging off the server will leave a head on the ground until you log back on.

If the head is left in a protected area, players authorised in the area can interact with it to access your inventory:

If the head is in the wilderness or you logged off while in combat, anyone will be able to access it.

The head can be attacked by players. If it is destroyed, you will die. The contents of your inventory and some of your experience will drop.