Nightmare Myu, who Myu calls Myutoo, is the nightmare counterpart of Invader Myu.
Of course, Myutoo is intensely evil. Myu is even jealous of her, because her ruthlessness is something the Irken Empire would like in an Invader. Myutoo looks a lot like Myu, and if Myu gets angry, you couldn't tell the two apart. Myutoo has a sister known as Anjtoo and a brother, the most evil of them all called Kromtoo. Her CUT Unit is SNUB, the Nightmare BUNS. Myutoo hates Myu and wants her away due to Myu's competative spirit. She also wants to overthrow the Nightmare Dimension, almost like Myu wants to conquer the Irken Empire. She rarely speaks, much unlike Myu.
- Myutoo is a pun on Myu and Mewtwo, the corrupted, powerful Pokemon.