Spiky Ball Trap

Spiky Ball Traps can be found in Lihzahrd Temple in Hardmode Underground Jungle Biomes.

When activated, dispenses an orange spiky ball that bounces several times, dealing around 90 damage to players and enemies; it bounces higher the further it has fallen. It has a cooldown of 4 seconds.

Tips
Very effective for home defense, especially using the new enemy triggered pressure plates.
 * Damage to players is doubled

Considering the Lihzard Temple usually contains dozens of Spiky Ball Traps, they are an efficient way to make specific underground farms. A box design the size of your screen with Spiky Ball Traps aligned on the ceiling of the box will kill a lot of mobs every second. The box should be 3 blocks thick and consist of the appropriate block for the biome you want (e.g. for a Crimson Mob farm you would use Crimstone Blocks, for a Jungle Mob farm Mud Blocks with Jungle Grass seeds etc). This will allow you to farm Mimics, Key Molds, a few Platinum coins every hour as well as rare mob drops, like the skull from skeletons or the Uzi from the Angry Trapper.