Jal-MejJak appears in the Inferno when TzKal-Zuk is at 20% health. They will rapidly heal TzKal-Zuk unless the player attacks them. Doing so causes them to stop healing TzKal-Zuk and start raining lava balls on the ground in front of them, similar to the effect at the Chaos Temple. Each lava ball does 5-10 damage. This damage can potentially be dodged, but doing so risks being hit by TzKal-Zuk, who can kill the player instantly. Thus, the preferred method is to kill them quickly with ranged or magic, while eating through the damage.