Head-butted a boulder. The boulder did not move. Natural selection filed this one under 'lessons'. The real Pachycephalosaurus (say it pak-ee-SEF-ah-loh-SORE-us) lived in the Late Cretaceous — its skull dome was up to ten inches of solid bone. Pure black vector ink with X eyes and hand-hatched shading, so it prints razor sharp at any size. Dark humor, best for teens and up. Thick matte vinyl that peels clean and re-sticks once or twice before committing — made for bottles, laptops and journals.