Twitchy, Spasm (3.5e Flaw)
From D&D Wiki
Your limbs twitch periodically.
Prerequisite: Dex 15+
Effect: During combat, every 1d4+1 rounds (determined at the beginning of each encounter) the character must make a successful Will save of DC 15 + Character Level or spasm, resulting in losing their turn completely. No action of any kind can be made during this round, excepting what is written below.