Lazure's Valkyrie Circlet

This is one of the developer outfits, designed after Lazure, who used to draw art at Re-Logic. It only appears inside Treasure Bags, which means an Expert or Master world, since a Classic world never produces the bags in the first place.

Every Hardmode boss bag can roll it apart from Queen Slime, and the chance is small. Nothing about how you fight improves your odds, so the practical approach is to keep killing bosses you were going to kill anyway and open the bags.

The clothing is social slot decoration with no defense behind it, but the drop is not clothing alone. Lazure's Barrier Platform and the Valkyrie Yoyo come down alongside the outfit, and the yoyo is a real weapon rather than a costume prop. For most players that pair is the actual reason to want the drop.