New ghost mob in minecraft

When you die, drop your stuff, and respawn, a guardian(your ghost) spawns and tries to prevent you from getting your stuff. It can fly low and can go through blocks. It is not effected by tnt, fire, or water. If you kill it, you get a ghost helmet shard, and when you craft a helmet out of it (built like a normal helmet is), it makes you invisible to mobs for ten seconds after you hit them.