Starring: Grey Griffin, Richard Steven Horvitz, Vanessa Marshall, Greg Eagles
Grim vs. Mom / Tastes Like Chicken - S1-E7
Continuity mistake: When Billy finds Grim sun bathing in "Tastes Like Chicken", Grim yells at him. This causes Billy's hat to pop off, showing he's surprised, but when that happens he is bald. Normally, Billy has red hair.
Grim vs. Mom / Tastes Like Chicken - S1-E7
Continuity mistake: Billy and Mandy are in night clothes during Grim and Billy's Mom's fight, but they're in regular clothes again after the combat.
Hoss Delgado: Give it to us straight, Goodburger. Is our little Remus.
Mandy: Billy.
Hoss Delgado: ...Billy, on the bullet train to Smartsville, or is he riding the slow pony to the rubber forest?
Fiend is Like Friend Without the 'R' - S1-E4
Trivia: Nergal is the villain introduced in this episode. "Nergal" originally was the name of the Babylonian God of Fire and Guardian of the Underworld. In the Bible, he is one of the demons allied with Satan himself. In the series Nergal is associated with the underworld and fire.