Giant Pearl

The Giant Pearl is a Pre-Hardmode accessory dropped by the Giant Clam mini boss after the Desert Scourge has been defeated. When equipped, it causes the player to emit light and inflict all enemies within a 3 block radius with the Pearl Aura debuff, which slows down their horizontal and vertical speeds considerably.

Trivia

 * Despite being a debuff, Pearl Aura's icon has a blue background like a buff.
 * Destructible projectiles, such as Chaos Balls or Water Spheres fired by Fire Imps or Dark Casters are slowed more the closer they are to the player, and can even be completely stopped.