The mutant’s vocal cords are substantially altered, allowing him to produce sounds both above and below the normal human auditory range. The culmination of this ability seems to be a focused shout, using the sonic vibrations on everyone in the immediate vicinity of the mutant.
Once per day, the mutant can let out a horrible shriek that affects everyone within a 10’ radius of him. Targets in the area of effect must save versus stun attacks or take 1d4 points of sonic damage and be deafened for 1d6+4 rounds. Those who successfully save are unaffected. Mutants with the mutation echolocation suffer a -2 penalty to save.