Wraith

Wraiths are Hardmode ghost-like Enemies that can travel through Blocks. They can inflict the Slow Debuff on the player. They have black bodies, which render them almost completely invisible in dark areas, but have two glowing red eyes that are visible from within the darkness. They spawn at the surface layer at night.

Wraiths appear to be flying, however within empty space they can only hover slightly off the ground. They can only fly upwards when they have foreground blocks to "swim" through.

Wraiths are immune to the Poisoned, On Fire!, Cursed Inferno, Venom, Confused, and Shadowflame debuffs.

Tips

 * Any structure raised least 8 tiles above the surface will prevent a Wraith from levitating up and through it.
 * Wraiths can be spawned pre-Hardmode by using a Wraith Statue.

Trivia

 * Wraiths are most likely a reference to Raymond. E. Feist's Riftwar Saga, where wraiths are described as black man-shaped clouds with burning red eyes, which is further referenced by the fact that they rely upon their target being too scared to move, similar to how they can inflict the slow debuff, hindering player escape.