The cookie is described as a "moist chocolate chunk cookie dipped in extra milk chocolate for a delicious chocolately treat." It's priced at $1.49.
I haven't been able to verify this but it looks like the new cookies are being added as a point-of-sale item (i.e. next to the case register) at new "pizza theater" redesigned locations.
Other things they're looking to try, in at least one location, include Sea Salt Caramels and Chocolate Peanut Butter Crunch Bars:
Photos by Domino's.