Halo Revenge

Some kids at school made fun of me for playing Halo. I gave them a halo.

Explanation

The joke plays on the word "halo". In a video game, it refers to the popular game "Halo". In the real world it means the ring of light above someones head. But in a dark twist the speaker takes it to mean something else. They "gave" a halo implying that they killed the bullies since people get halos when they die.