Paralyzing Fists

(Drow of the Underdark, page 51, DnD 3.5)

[General]

You can make multiple unarmed attacks to paralyze an opponent in a single round

Prerequisite

Improved Unarmed Strike, Stunning Fist, WIS 15

Benefit

When two or more of your "Stunning Fist":feats/players-handbook-v35--6/stunning-fist--2802/ attacks succeed in stunning a single foe in the same round, that creature must make another Fortitude saving throw (DC 10 + 1/2 your character level + your Wis modifier +1 for each successful "Stunning Fist":feats/players-handbook-v35--6/stunning-fist--2802/ attack). On a failure, that creature is paralyzed for 1d2 rounds instead of being stunned for 1 round. Creatures that are not subject to extra damage from critical hits and creatures that are immune to stunning cannot be paralyzed in this manner.