For future Sonic the Hedgehog video games and comic books: (After the events of Sonic Forces) What if... the Phantom Ruby send and teleport Infinite the Jackal from Sonic's world (a.k.a. Mobius) to planet Earth (human world) for some reason?
Sonic the Hedgehog series, and Mega Man Zero, Megaman series:
1.) Shadow the Ultimate Lifeform = Zero
2.) Biolizard = Omega
Elf meets Infinite the Jackal (from Mega Man ZX Prequel, Megaman series, and Sonic Forces, Sonic the Hedgehog series)
(Part 2) For Sonic the Hedgehog series (video games comic books and more): Imagine if... Infinite the Jackal and Shade the Echidna secretly get marry and have a new child of their own (or possibly transform/fuse together into a new character) for some reason?
Super Spark the Electric Jester vs. Tirek, Cozy Glow, and Queen Chrysalis (from Spark the Electric Jester, and My Little Pony Friendship is Magic series)
Imagine if... something or someone could find and turn the crashed Egg Carrier (from Sonic Adventure), and destroyed G.U.N.'s Prison Island (from Sonic Adventure 2 Battle) into something else for some reason? (from Sonic the Hedgehog series)
E-102 Gamma the most forgotten character (from Sonic Adventure, Sonic the Hedgehog series)
@NibrocRock Shadow the Hedgehog reaction of Sonic wearing clothes with dalmatian spots.
Shadow: (facepalm) Why, Faker?
If Silver the Hedgehog kills Mytyl Kamizono for some reason, Copen will blame Silver for everything that he cause very badly. (from Sonic the Hedgehog, and Azure Striker Gunvolt series)