The Cursed Skull (and the Dragon Skull on Old-gen console, Windows Phone, and 3DS) is a flying enemy found only in the Dungeon. It is similar to the Meteor Head, with high damage, slow speed, and the ability to travel through tiles. It floats slowly towards the player, occasionally stopping to float in a circle around them for a while, before suddenly lunging forward to attack, similar to the Eye of Cthulhu. When striking a player, the Cursed Skull has a small chance to apply the Curseddebuff. This renders the player unable to use items, including Weapons, Potions, and Grappling Hooks, making it very difficult to avoid further damage.
Cursed Skulls can be attacked through walls with melee weapons. Weapons with long range like Spears work well. This may, however, result in drops being trapped inside of the wall beyond the player's reach.
Cursed Skulls and Dragon Skulls can, rather rarely, drop more than 3/6Bones when defeated.
It is best to farm them for the Nazar since they spawn more often than the few other enemies that drop the Nazar. It is also best to do this before Hardmode to save time farming for the other ingredients for the Ankh Shield.
Trivia
Dragon Skulls are colored according to the color of bricks of the Dungeon. If the Dungeon has pink bricks, Dragon Skulls will be orange. Green brick will result in green Dragon Skulls spawning, and blue Dragon Skulls spawn only in Dungeons made of blue bricks.