A character pack for Sonic Robo Blast 2. After being disowned by their creator after their failure to acquire the Chaos Emeralds in Sonic R, Metal Knuckles and Tails Doll join Sonic and Co. to take down Dr. Eggman! This duo of doppelgangers have returned from their previous outing with some new tricks that players can utilize to explore stages in brand new ways, similar to that of their original organic counterparts.