This extraordinary ability makes a creature's very presence unsettling to foes. It takes effect automatically when the creature performs some sort of dramatic action (such as charging, attacking, or snarling). Opponents within range who witness the action may become frightened or shaken.
Actions required to trigger the special quality are given in the creature's descriptive text. The range is usually 30 feet, and the duration is usually 5d6 rounds.
This ability affects only opponents with fewer Hit Dice or levels than the creature has. An affected opponent can resist the effects with a successful Will save (DC 10 + 1/2 frightful creature's racial HD + frightful creature's Cha modifier; the exact DC is given in the creature's descriptive text). An opponent that succeeds on the saving throw is immune to that same creature's frightful presence for 24 hours. Frightful presence is a mind-affecting fear effect.