The Beheaded's Head

This costs more separate ingredients than any other vanity set in the game, and one of them depends on which evil biome your world rolled. The head is the awkward part, because it is built at an altar. Altars are otherwise a pre-Hardmode station that people smash on sight the moment they get a Pwnhammer, and this is one of only two things in the entire Hardmode crafting tree that sends you back to one. Leave a couple standing if you plan on making this.

Throwing the head into Shimmer breaks it down into your world's evil material, rotten chunks in a Corruption world and vertebrae in a Crimson one. Drunk worlds are the interesting case. The two evils swap places at the start of each in-game day there, so the same helmet decrafts into different material depending on when you drop it in. Wait a day and throw the next one in for the other material.

It is a crossover with Dead Cells, and it copies the default appearance of that game's player character. The tooltips carry the reference further than the sprites do. The cuirass nods at the Malaise, the sickness driving that game's plot, while also bending the old line about an apple a day, and the trousers play on possession being nine tenths of the law, which works as both a legal phrase and a joke about what is wearing the body.

All three pieces sit in social slots and change nothing except how you look.