Slaughter Fodder (3.5e Flaw)
From D&D Wiki
You leave yourself open... a lot.
Effect: Due to your long life of getting beaten on, you lose 1 HP per lvl (max HP can not be reduced lower than total HD), and you still can't learn your lesson. You provoke attacks of opportunity after every standard action except for your own attacks of opportunity.
Roleplaying Ideas: An extra-planar great old one has cursed you with clumsiness... yeah, that sounds believable... you're definitely not just a klutz.