You are covered with sharp, bony spines. For each schtick spent on this power, add +2 to your Damage values for unarmed hand-to-hand attacks. You may not gain more than 8 Damage in this way.
If you have some natural weaponry in mind other than spines - jagged teeth, wicked claws whatever - describe how it looks accordingly. The damage effect remains the same no matter what form of extra damage you pick. We just thought_abysmal spine_ sounded cooler than "extra damage".
Abysmal Spines can also add damage to Tentacles and other physical attack forms. They can be used with either Powers or MartialArts. DamageImmunity to Unarmed attacks (not Creature Powers) protects from this.