The Selenian is a Hardmode, post-Lunatic Cultist enemy that is spawned by the Solar Pillar during the Lunar Events. It is a ground-based enemy that wields two flaming swords. It has a spinning attack that causes it to move faster and reflect the player's projectiles.
It can reflect bullets, arrows and darts, but not rockets. It additionally reflects the following weapons' projectiles:
- Selenians take triple damage (after having calculated defense) when spinning.
- Unlike in PvP, reflected Chlorophyte Bullets will chase the player. Due to this, it is inadvisable to use them in the Solar Pillar area.
- Vampire Knives will not heal the Selenian when they are reflected and hit the player.
- The word "selenian" means "pertaining to the moon" and refers to Selene, the Greek goddess of the moon and sister of the sun-god Helios.
- The Bestiary entry for the Selenian: "These acrobatic celestial warriors can deflect incoming threats whilst spinning with their solar-infused blades."