Archie Sonic X Issue 21 is the twenty-first issue of the Sonic X comic series published by Archie Comics.
"Sub-Sonic": After being trapped on Earth all this time Sonic, Tails, Amy and the others may have finally stumbled upon a way to get back to their home world. Will the daring plan pay off or just put Sonic and friends in a mind-bending dilemma of universe-al proportions?!
After waking up from a terrible nightmare, Sonic wakes up knowing that his nightmares are being cause by Chris talking too much about his Robonicles. Chuck reading the newspaper discovers that his former lab partner Alexander Pell has worked out a way to travel through different dimension and will be testing it today in his lab. Chuck explains that he used nano-technology to make the device and found an extremely rare mineral called Rubinite. Doctor Eggman uses three new robots that resemble the Robonicles and plans to steal the device to shrink Sonic. Sonic, Tails, Amy, Chris and Chuck at the lab are about to watch the test, when Dr Eggman, Decoe and Bocoe in their new robots crash in. Sonic, Tails, Dr Eggman, Decoe and Bocoe are shrunk by the device. Sonic and Tails run over to a toy plane to escape from Dr Eggman's robots but the robots grab onto the plane and they all crash into the toy store across the road. Sonic and Tails escape from Dr Eggman, Decoe and Bocoe by posing in a shelf full of animal toys. Tails confused at one of the dolls when he realises it's supposed to be him and is freaked out by it.
Chuck and Pell attempt to fix the device before it's too late. Sonic and Tails split up, Sonic running away from Dr Eggman and Decoe and Bocoe chase after Tails. Tails hides in a pink house away from the robots who want the girl doll that is in front of the house. Dr Eggman grabs a Truckasaurus truck and chases after Sonic. Chuck uses Diode inside the device which will give them enough power to change them back. Sonic successfully gets away from Dr Eggman while Tails uses a pink car to escape from the robots. Tails crashes the car and are pined next to an exit door, which is impossible to move because of their height. Amy finds Sonic and Tails and uses the device to make everyone normal again. Sonic and Tails quickly dodge Dr Eggman's final blown and escape. The damage from the crash has caused all of the Robonicle toys to be broken and Chuck has no choice but to buy them all for Chris.