MelodyQuill
Sonic the Hedgehog is enjoying life on Earth and with his new surrogate older sisters, the Rainbooms, despite his wanting to use his powers as a hero and with some new changes and additions to daily life. Especially as his favorite Rainboom, Rainbow Dash, seems to have a reciprocal romantic interest in someone else.
But when some of the Rainbooms leave Canterlot City for a wedding out of town, Sonic and the others (Twilight and Fluttershy) are attacked by a vengeful Dr. Robotnik and his new ally, a red echidna warrior named Knuckles, who is as strong as Sonic is fast. However, Sonic and the remaining Rainbooms are saved by a two-tailed, highly intelligent young fox named Miles "Tails" Prower, who tells them that Knuckles and Robotnik are looking for the Master Emerald, an ancient, universal relic with unlimited power that could also provide answers to the origins of the Rainbooms' own magical abilities connected to their geodes.
Sonic and the Rainbooms, along with their new friend Tails, must find the Master Emerald first before Robotnik does. The fate of the universe depends on it.
A crossover of "Friendship is Magic: Equestria Girls" and the 2022 movie "Sonic the Hedgehog 2".