So designing a new Eidolon with tbe serpentine base form. Using such he qualifies for the Constrict evolution
An eidolon gains powerful muscles that allow it to crush those it grapples. Whenever the eidolon successfully grapples a foe using the grab evolution, it deals additional damage equal to the amount of damage dealt by the attack used by the grab evolution. This evolution is only available to eidolons of the serpentine form
My original question is this do you double the damage done by the original attack or do you reroll the original attack damage?
The reason i need this clarification is because of the Final Embrace feat tree, with Final Embrace Master stating
Benefit: Double the number of damage dice for your constrict special attack.
As a follow up bonus question. My Eidolon has 4 Natural Primary Claw attacks. Can he hit with a claw, grab the opponent dealing constrict damage. Drop the poor thing, than rinse and repeat the other 3 attacks? Or do i need to make the grab the last attack?