Minecraft wiki entry for Spawner_traps, associated text: Mob spawners can be neutralized by placing torches to light up any dark areas around the spawner. With the exception of blaze spawners, a single torch placed on the spawner is sufficient to disable it. Because blazes can spawn up to light level 11, multiple torches (light level 14) are required to neutralize a blaze spawner. There are six different mobs that can spawn. They are separated into two categories: the two-block high tall mobs - zombies, skeletons, and blazes - and the one block high short mobs - spiders, cave spiders, and silverfish. Similar variants such as the zombie villager are not included in this list.