Noob Boss
A Noob Boss is a creature with powers and abilities far beyond those of ordinary ones. Some have additional (20) Material Points, some have perks such as Mirror Skin and Self Destruct with total list unknown - some may steal rostogols as far as we know.
The Noob Boss was created to make afk farming a bit more fun (fun as more likely to drop items).
Very Rare Drops
There are probably more.