Developer Items

In Terraria there is an option to make an expert mode world. An expert mode world makes enemies and bosses more difficult, but bosses will drop special items, and have a 5% chance to contain a developer set. A developer set contains a costume of the entire costume plus wings. The best strategy is to get as many hard mode boss summons as possible, because developer sets only drop from hard mode treasure bags. In my opinion the best boss for this is the golem, because you can easily make a power cell farm in the temple.