- "If my head were any harder, you could use it for a cannon ball."
- ― Pazu, Castle in the Sky
- "It would probably take a bolter shell to crack that thick skull of his."
- ― Commissar Ciaphas Cain, on Jurgen
- "I shall break out of this cell using the hardest substance known to Mankind! MY HEAD!"
- ― Kremmen of the Star Corps
The power to have an abnormally strong and durable skull. Variation of Unbreakable Bones.
- Hard Head
- Strong Skull
The user's skull is incredibly durable and strong, enabling for powerful headbutts to no ill effect.
- Enhanced Combat
- Horn Protrusion
- Megaton Kick
- Natural Weaponry
- Power Fists
- Psychic Shield - Having such a hard-headed as to be immune to telepathy
- Unbreakable Bones
- User's skull may only be able to endure a certain amount of impact.
- Enhanced strength and durability may be limited to the skull.
- User may have a small brain due to the skull being so thick.
- Wushu Helmet (Xiaolin Showdown)