Cursed Hammer

The Cursed Hammer is an enemy found in the Underground Corruption. It has a maximum of 200 HP. When you encounter it, it will first spin (or, charge), then move straight at the player, going through blocks to get to them. This mob is a non-solid enemy, similar to the Eater of Worlds and other such enemies. Upon hitting the player it has a chance to give you the Cursed Debuff which stops you from using any items for 4 seconds. It can deal around 108 Damage to unarmored players without any defensive items.

Similar to the Underground Hallow version, the Enchanted Sword, it is not immune to Knockback,and a player may disrupt it's attack while it charges. Ranged weapons are recommended, as the player will not have to get close. In smaller, more enclosed areas, spears are a good choice as they will hit the Cursed Hammer through the walls (as with all non-solid enemies) and quick weapons like Phasesabers can keep them at bay and deal large amounts of damage too. This makes it a relatively easy enemy to destroy, as it won't be able to reach the player.

Trivia
As Excalibur has the same sprite as the Enchanted Sword, the Cursed Hammer was speculated to be a preview of a future Hammer. This has proven to be false though, as development on Terraria has ceased.