The Morbid Harvester is a reaper-like creature whose sole mission is to kill every living thing in the Minecraft world. For every entity hit, he regenerates 2.5 hearts. If you hit him too many times without him being able to hit back, he will start blocking. While blocking, he can’t take damage. If you force him to block for longer than his liking, he will do a get-back move, creating a blastwave around him, knocking back any enemies as well as healing himself back up. This harvester has 250 hearts and very high defense.
See also: another killing creature Void Monster Mod
He can be summoned in by putting a Wither Skeleton Skull on top of two Obsidian blocks, and right-clicking it with a Nether Star. If you, against all odds somehow manage to kill him, you will be rewarded with a great xp yield and 1-2 (depending on if your sword has looting on it) of his +40 attack damage arms. But beware, upon his death, he explodes into a rain of deadly arrows, which not even the best enchantments can save you from!
There are currently three new enchantments added by this mod, all of which are going to be essential to beat the Morbid Harvester.