Monster Spawners are blocks with a transparent black, cage-like lattice structure found in various locations. Inside the block, there are flames that don't give off any light, and a miniature spinning version of the mob that is spawned, which slowly increases speed until the next mob is spawned. When mined with a Pickaxe, they drop experience. They are one of the few blocks not usable/placeable in Creative Mode, though it is possible to get this block throughout the /give command.
A spawner will create mobs provided there is space for the mob to be generated and the light level within the spawning radius remains below seven. Mobs are created within an 8x8x3 high area centered on the spawner block's lower left corner. Note that mobs can spawn in any dark space within range, even if the spawner is fully lit. The spawner will only spawn mobs if the player is within 16 blocks of it. They also make a loud ticking sound. A common trend among seasoned players is to create mob traps around monster spawners for an easy way to gather that mob's resources.
Note:Monster Spawners can also be obtained through mods and hacks, such as TooManyItems. They cannot be obtained when mined by an item with theSilk Touchenchantment.
Mob spawner has the ID of 52 and is named as "Monster Spawner" in-game.
Mob spawners typically spawn regular enemies and cannot be changed. With the use of mods and add-ons, however, the player will become capable of changing mob spawners.
Spawners do not naturally spawn endermen because of their ability to hold blocks.
Spawners also do not naturally spawn creepers because of their ability to explode.
Unlike most other transparent blocks, it is possible to place Torches on a Monster Spawner.
Even though a mob figure is much smaller than the actual mob, Ghast figures and Giants are too big for the spawner to be seen.
Monster Spawners can spawn up to four mobs at once.
Very rarely, a Monster Spawner can be found in out-of-the-ordinary locations.
In Minecraft XBLA (Before the Christmas update 2012), mob spawners would only show pigs but would spawn things other than pigs.