Demon Eye

Demon Eyes fill the sky over most surface biomes after dark and are thickest above forests. They clear out at dawn. On the night of a new moon the game turns the dial up and they arrive in numbers that can genuinely overwhelm a fresh character caught outdoors without a roof. Around Halloween the costumed versions take over the spawn slot instead. There are fourteen appearances in total and every one of them drops the same things at the same odds, so there is no variant worth hunting specifically.

It points itself at you and commits. The turn rate is poor, so one that overshoots needs a moment to swing back around, and that moment is the whole fight. Anything you hit it with that carries knockback throws it off its line and buys you another window, which is why a weak weapon with good knockback outperforms a stronger one here. Walls bounce it upward rather than stopping it. Water it cannot enter at all.

• Cut a short hook into a hillside, an upside down L, and stand in the foot of it. Anything that follows you in bounces up into the ceiling and never reaches the corner.
• A sealed box with a single one tile opening lets your shots out and keeps them out. A Wooden Bow fired from inside one clears a whole night safely.
• Standing fully underwater makes you untouchable by them, and you can still swing a broadsword or fire from down there.
• Swing a sword and change which way you are facing between swings. The knockback keeps batting the same eye back and forth inside your reach until it dies.

Like zombies, each one rolls a size when it spawns. Oversized ones carry more health and defense and shrug off knockback, which is exactly what breaks the sword juggling trick above. Undersized ones move faster and are awkward to land hits on. Separately, the named variants have a chance to bring their alternate size twin along with them, so those tend to arrive two at a time. The plain Demon Eye and the Halloween costumes always come alone.

• The Eye of Cthulhu, its servants and the Wandering Eye are all built on this design.
• During a Blood Moon the eyes are supposed to twist together into a knot of blood and eyeballs, which is where a Drippler comes from.
• The Dilated Eye looks like it should be the one to farm for Black Lenses. It is not. Every variant shares the same table.
• The Cataract Eye takes its name and its clouded lens from the real condition. The Sleepy Eye is a nod to the Monoeyes of Kid Icarus.