Shark Tooth Charm
Item 5AbjurationConsumableMagicalTalismanSource Core Rulebook pg. 569 2.0Price 23 gp
Usage affixed to armor
Activate 
command;
Trigger You attempt to Escape using Acrobatics for your roll, but you haven't rolled yet;
Requirements You are an expert in Acrobatics
This dried seaweed bracelet is lined with charms shaped like small shark teeth. When you activate the bracelet, if you roll a success on the triggering check, you get a critical success instead (if you roll a critical failure, you get a failure instead). If you fail the Acrobatics check against a grabbing creature, the creature must either release you as a free action or take 2d8 piercing damage as shark’s teeth momentarily emerge from your skin.