Add animated weapons to Minecraft.

 These can be part of a loot box or as the weapon of a hostile mob. When taken from the loot chest or if their host is killed, they rise up and attack the player.

These could be specifically for desert or jungle temples as an additional kind of  'trap', especially if enchanted. But if the weapon drops on death, at least some of the enchantments should carry over—you've earned it, even if the durability itself is trash.

An animated weapon might also be creatable using wind charges as part of the recipe, as a base guardian or a nasty surprise for a thief.