"Blockhead"
Bouncin' Boneheads Series 1, #022

Blockhead is a moron. Of all the Jojos this guy is the hardest to teach. Hes a real know it all and is totally intolerant of opinions other than his own. As luck would have it, Blockhead is one of the rarest boneheads so if you can get Blockhead, he makes a valuable addition to your collection.