Pixie

The Pixie is a Hardmode enemy that hovers a limited height over ground, commonly spawning in The Hallow at the surface layer. It emits a fair amount of flickering light, and can inflict the Slow or Silenced debuffs. It always drops Pixie Dust, a common Hardmode crafting material.

Pixies are immune to all damaging debuffs (On Fire!, Poisoned, and Cursed Inferno).

Trivia

 * The Fairy Bell summons a Fairy that looks similar to a Pixie, and serves as a light source to players.
 * (Needs confirmation, possibly a bug) Pixies seem to always drop Fast Clock and Megaphone simultaneously.