Amongst the Cosmos/Yh'olirgh's Tooth

The Yh'olirgh's Tooth is a Pre-Hardmode dropped by any Boss with a 10% (1 in 10) chance when the  is used. When used, it gives the player the Yh'olirgh's Blessing buff for 1 minute, which increases all damage types and critical strike chance by 25%, as well as halving the player's health.