You just redefined the meaning of 'friend'.
My head spins with possible scenarios
- 2 friends visiting dead boyfriend's grave. Overcome by emotions the vic sobs "I never meant to kill him" , then gets offed in revenge.
- 2 friends visiting dead boyfriend's grave. Vic says "You used to be even less fun when you were still alive". Need I go on?
- 1 friend visiting dead boyfriend's grave. Vic says "Pity we can't do that hot dying scene again". Then the grave opens and the zombie gets his revenge.
- ...