Knuckles the Echidna Plushie Backpack Set - Bundle with 18" Knuckles Plush Doll with Carrying Straps Plus Stickers, More | Sonic the Hedgehog Gifts for Kids, Boys. This Knuckles the Echidna set includes one 18" Knuckles plush doll with adjustable carrying straps to bring Knuckles with you anywhere. Sure to be a hit with Sonic the Hedgehog fans, this Knuckles plushie set is great to give to the Sonic or videogame fan in your life! Take Knuckles with you wherever you go! These adjustable shoulder straps are great to keep Knuckles on your back with you. Plush features a small compartment for storing small items. Officially licensed Sonic the Hedgehog Knuckles plushie set for boys and girls alike also comes with Sonic stickers and a Rex-Man door hanger.