Hellfire

Hellfire is a channeled warlock AoE spell that deals fire damage in periodic pulses. This spell is very peculiar because it also deals damage to the warlock per pulse, and the warlock can actually die if his health pool is depleted while he channels the spell. Due to this, it's very common to see warlocks trying to Hellfire themselves to death when the raid is wiping on an encounter to avoid durability loss. As a common courtesy, healers are encouraged to heal warlocks who are trying to hellfire themselves out of a repair bill.