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 + ½ 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.
A number of epidemiological studies suggest small increases in risk of childhood leukemia with exposure to low frequency magnetic fields in the home. However, scientists have not generally concluded that these results indicate a cause-effect relation between exposure to the fields and disease (as opposed to artifacts in the study or effects unrelated to field exposure). In part, this conclusion has been reached because animal and laboratory studies fail to demonstrate any reproducible effects that are consistent with the hypothesis that fields cause or promote cancer. Large-scale studies are currently underway in several countries and may help resolve these issues.