Defiant Luck

You can sometimes defiantly shrug off spells and attacks that would kill a lesser creature.

Prerequisite: Human.

Benefit: Once per day, after you roll a natural 1 on a saving throw or a critical hit is confirmed against you, you can either reroll that saving throw, or force the creature that confirmed the critical hit against you to reroll the critical confirmation roll. This does not stack with other effects that allow you to reroll a saving throw or an attack roll. You may only make one reroll.

Special: If you are using the optional hero point system (Advanced Player’s Guide 322–324), you can also spend 1 hero point when a critical hit is confirmed against you to have the opponent reroll the critical hit confirmation roll.

Source: Advanced Race Guide