SRD:Fear

Fear (Su or Sp)
Fear attacks can have various effects. In most cases, the character makes a Will saving throw to resist this effect, and a failed roll means that the character is shaken, frightened, or panicked.

Becoming Even More Fearful

Fear effects are cumulative. A shaken character who is made shaken again becomes frightened, and a shaken character who is made frightened becomes panicked instead. A frightened character who is made shaken or frightened becomes panicked instead.

Fear Aura (Su)
The use of this ability is a free action. The aura can freeze an opponent (such as a mummy’s despair) or function like the fear spell. Other effects are possible. A fear aura is an area effect. The descriptive text gives the size and kind of area.

Fear Cones (Sp) and Rays (Su)
These effects usually work like the fear spell.

Frightful Presence (Ex)
This special quality 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 ability 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.

If a fear effect allows a saving throw, it is a Will save (DC 10 + 1/2 fearsome creature’s racial HD + creature’s Cha modifier; the exact DC is given in the creature’s descriptive text). All fear attacks are mind-affecting fear effects.