Skeleton

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 (crafting material) which is essential for crafting a Grappling Hook, though other Hooks can be acquired through other means.

Skeletons are immune to the Poisoned debuff.

They can also be spawned by powering a Skeleton Statue.

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).

Trivia

 * Skeletons appear in at least 49 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 /.
 * 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.

History
Squelette 해골 Skeleton Skeleton Скелет