King Slime Trophy

A trophy is the boss equivalent of an enemy banner, except it does nothing whatsoever. No stat, no set effect, no bonus of any kind. It is wall decoration and bragging rights, dropped uncommonly by most bosses, and the entire system is a joke about trophy hunting: you mount a piece of the thing you killed on a rack and hang it up.

King Slime gives you a katana coated in slime. That is the ninja sealed inside him, and it is one of the very few places the game admits he is in there. Nothing during the fight itself tells you. He is also cheap to resummon and gets killed repeatedly for other reasons, so this trophy tends to arrive on its own rather than needing a deliberate farm.

• The Eye of Cthulhu leaves a tooth, the Eater of Worlds an eye, and the Brain of Cthulhu one of its lobes.
• Queen Bee gives up a leg, which is a bee's knees pun, while Queen Slime hands over a wing feather with pink slime still on it.
• The Wall of Flesh drops its tongue, which ties back to both its unique death message and the debuff only it inflicts.
• Plantera's is her bulb, the same object you smash to summon her in the first place.
• Golem's is the chestplate design, which you have walked past on Lihzahrd doors without registering it.
• Skeletron gives a bone and Skeletron Prime its jaw, and the Twins split into Retinazer's cannon and Spazmatism's flamethrower.
• The Moon Lord parts with his heart, the Empress of Light her tiara, the Ice Queen her crown, and Santa-NK1 its head with the mask torn away.

The Celestial Pillars carry boss health bars and give nothing between the four of them, which catches out anyone trying to fill a complete wall. Dreadnautilus had one designed, built around its tendrils, and it was cut before release. A couple of bosses exclusive to the older console and handheld versions also went without.

A handful never come off a boss at all. The Angler hands them out at random for quests, so a complete collection means grinding fishing alongside the boss list. They are fish rather than boss parts, which makes them look a little odd hanging next to the rest of the wall.

Pumpkin Moon and Frost Moon bosses only start dropping trophies deep into the wave order, with the chance climbing from there. That turns them into a test of whether your arena and gear can hold the event together long enough, rather than a test of whether you can kill the boss. On the oldest versions the rule was blunter: one specific wave, guaranteed drop, nothing before it.

They mount on a wall the way a weapon rack does. A few glow faintly, which is worth knowing because that glow does not satisfy a housing light requirement, so a trophy hall still needs real torches or lamps if you want anyone living in it.

Ocram was an old console and handheld exclusive, and his trophy left with him when those versions caught up to the modern game. Copies already placed in a world were quietly rewritten into Lunatic Cultist Trophies, while ones sitting in inventories turned into a pile of gold. There is also a minimap quirk worth knowing while you are collecting: the compass rose, wall anchor and ship's wheel all read as trophies down there, and the life preserver does not.