Red Devil

The Red Devil is a hardmode enemy that spawns in The Underworld after any of The Destroyer, The Twins, or Skeletron Prime has been defeated. It can be considered a harder version of the Demon.

While the Red Devil itself does not cause much contact damage, its trident attack is capable of dealing large amounts of damage even to players in Hallowed armor. The tridents are similar to the Demon's scythe attack, but do more damage and do not need to accelerate.

While this enemy (and the lava bat) are considered hardmode enemies, they can spawn in normalmode worlds for some reason and drop their items. (Confirmed on a World that definitively was not in hardmode. However i had defeated The destroyer and the twins in that world.)