Sonic Boom (2014)

S2E4 Alone Again, Unnaturally

Sonic and Tails are busy creating a device aimed at boosting Sonic's speed. However, Sonic's new velocity causes him to vanish unexpectedly. Tails becomes anxious, fearing he may have lost his friend for good. Meanwhile, Sonic finds himself in a strange dimension, surrounded by spectral figures of his companions, though unable to reach them. As Eggman launches an assault, the rest of the team fights back, determined to shield Tails while he devises a way to bring Sonic back home.