File:Timed lava.png

Summary
The external view of a timed lava damaging mechanism for an XP-giving mob grinder. One button press will damage the front mob in the row by dispensing lava onto the netherbrick fence, and retracting it a bit later. Since the mob's feet are still in the water, the burn damage will stop immediately when the lava is retracted, allowing the damage to be timed very accurately.