The party Mob:
This is a party mob, it dissappears after 5 minutes if it's not attacked. It also has 10x more hp than normal mobs, and is a bit stronger. Of course it also gives way more xp. There are party giants too. They have (I think) 100x the hp of a normal mob. And of course give WAY more xp. There are also Champion party mobs, who own 2x10 the hp (20x). Also give double the xp of a normal party mob.