Narcolepsy (3.5e Flaw)
From D&D Wiki
Summary: You have a tendency to fall asleep at random times.
Effect: Whenever you don't do something for three or more round. You must make a Will Save (DC of 15) to avoid falling asleep. If you fail you fall asleep, and stay asleep for 1d3 rounds or until disturbed. All sleep spells succeed against you, even if you are normally immune to them.
Benefit: Bonus Feat