Magma Spears have 120 uses and are simply used to hit mobs. When in the overworld, they deal 3 1/2 <3. However, when in BlackNether, they deal 7 <3 and 5 <3 when 2/3 damaged. They can stack in 16. Whenever the player hits a mob with a Magma Spear, there is an 88% chance that whatever got hit will receive venom with the same effects as a Cave Spider's venom.