Moon Stone

A Moon Stone is an accessory that rarely drops from Vampires during a Solar Eclipse, a Hardmode-only event. It grants the same stat bonuses as the Sun Stone, however only during the night.

The stat bonuses are:
 * +10% melee speed
 * +10% damage (all types, including minion)
 * +2% critical strike chance
 * +2 HP/s life regeneration
 * +4 defense
 * +15% pickaxe speed
 * +50% minion knockback

Trivia

 * Possibly a reference to the Moon Stone in Castlevania: Symphony of the Night.

History
This could be a reference to the lego series Monster Fighters