Wither Skeletons are a type of hostile mob found in the game Minecraft. They are tall, dark, and skeletal creatures that spawn primarily in Nether fortresses. Wither Skeletons wield stone swords and have a chance to inflict the Wither effect, which gradually drains health. These mobs are known for their unique drop: the Wither Skeleton Skull. Collecting three of these skulls allows players to summon the Wither, a powerful boss mob. Wither Skeletons are more challenging than regular skeletons due to their higher health and damage output, making them a notable threat in the game.