Fiendship is Tragic is an episode of The Grim Adventures with Billy, Mandy, Felicity and Toby.
In this sequel to "Son of Nergal", Nerissa comes back from the Center of the Earth after being lonely and trying to make friends with her. She comes over to Endsville Middle School to make friends. Lamont and Sonnet tries mocking her, her voice and her appearance, she threatens to kill them and take over their entire appearance.
- Mrs. Winterwad
- Nergal Jr.
- The first appearance of Nergal and Nergal Jr.