The Nightmare is a large, black, wyvern-like creature with a large column of teeth and large horizontal wings. It drops the Nightmare scale which is one of the ingredients to craft the Big Bertha, Alternatively it can be used to craft a Three-bladed sword: The Nightmare Sword!! It also drops rotten flesh and the zookeeper shard upon death.
HP: 125/250/500/750/1000 (Varies on Size)
Attack: 15/30/60/90/120 (Varies on Size)
Defense: 11/12/14/16/18 (Varies on Size)
The Nightmare spawns in the Danger Dimension which is the dimension where you find floating islands. It is not particularly rare if you can fly above tree level. If you want to fight it easier, you can spawn it from the ancient dried spawn egg.
The Nightmare is a very difficult boss as it can vary in size and damage. It is stronger than every boss except Mobzilla, The King, and The Queen.
It is recommended to have the full Ultimate set, Anything weaker than that will get you eaten alive! It drops Zookeeper shard('s), feather('s), item frame('s), raw beef, rotten flesh and nightmare scale(s).
The Nightmare is based of the creatures in the movie Pitch black.