Skeletons are Enemies that spawn in the Cavern layer. They follow the Fighter AI, and can open Doors. Unlike Zombies, they do not require a Blood Moon to do so. They can drop a Hook which is essential for crafting a Grappling Hook, though other Hooks can be acquired through other means.
In Expert mode, some skeletons throw bones which deal 2x their base melee damage (also multiplied by 2 due to it being expert mode, making the damage 4x the normal mode base damage as shown below).
- Activating a Skeleton Statue with Wire will summon a Skeleton. Activating a Bone Skeleton Statue, a statue only found in Expert mode worlds, will spawn a Skeleton capable of throwing bones, even in non-Expert mode worlds.
- Skeletons appear in at least 50 different forms in the game, being: The 7 Skeleton forms, the 4 Angry Bones forms, Skeletron, Skeletron Prime, Skeleton Archer, Undead Miner, Armored Skeleton, Tim, Rune Wizard, Undead Viking, Armored Viking, Dark Caster, Cursed Skull, Giant Cursed Skull, Bone Lee, Tactical Skeleton, Skeleton Sniper, Skeleton Commando, 4 Blue Armored Bones forms, 4 Rusty Armored Bones forms, 4 Hell Armored Bones forms, 2 Necromancer forms, 2 Ragged Caster forms, 2 Diabolist forms, Dungeon Guardian, Hoplite, Dragon Skull /, Vampire Miner / and Skeleton Merchant.
- The Martian Halloween variant is a possible reference to the movie Mars Attacks.
- The Astronaut Skeleton could be a possible reference to the Vashta Nerada from Doctor Who.
- The Astronaut Skeleton is misspelled as "Astonaut Skeleton" in the game code.
- 电脑版 1.3.5：Regular, Headache, Misassembled, and Pantless Skeleton sprites updated.
- 电脑版 126.96.36.199：Can now drop its own respective banner.
- 电脑版 1.2：
- Headache Skeleton, Misassembled Skeleton and Pantless Skeleton variants introduced.
- Now has a chance to drop an Ancient Iron Helmet, an Ancient Gold Helmet, a Bone Sword, and/or a Skull.
- 电脑版 1.0.3：Sprite updated. Original sprite: