Needs review
Source: Complete Warrior

Description: You can paralyze a humanoid opponent with an unarmed attack.

Prerequisites: Improved Unarmed Strike, Stunning Fist, Base Attack Bonus +10, WIS 17

Declare that you are using this feat before you make your attack roll (thus, a missed attack roll ruins the attempt). Against a humanoid opponent, you can make an unarmed attack that deals no damage but has a chance of paralyzing your target. If your attack is successful, your target must attempt a Fortitude saving throw (DC 10 + 1/2 your character level + your Wis modifier). If the target fails this saving throw, it is paralyzed for 1d4+1 rounds. Each attempt to paralyze an opponent counts as one of your uses of the Stunning Fist feat for the day. Creatures immune to stunning cannot be paralyzed in this manner.

Special

A fighter may select Freezing the Lifeblood as one of his fighter bonus feats.