Nightmares ! is an episode of Billy & Mandy.
Grim, Billy & Mandy ran across Irwin several times as he wants Mandy to love him and Billy is counting how many times is Mandy beating Irwin. At night, Mandy dreams about Irwin & her getting married and as she woke up, it was morning and Irwin was calling her through the doorbell. Mandy comes out of the house, slaps him and quickly get inside the house. Irwin says why she beat her as no one answers him while Billy counted it as 1000th time as Mandy beat Irwin and Grim started laughing in an evil way.
- This is one of the few episodes where Billy & Grim had appeared a few times.