Robotnik's next stop in his time-travel is the Middle Ages, where the second emerald is. Sonic follows him, but Robotnik, with the unwilling help of a local wizard, obtains the emerald and takes over the kingdom.

Sonic frees a prisoner who has been locked at Robotnik's Fortress for 30 years who wants to find his long lost girlfriend which Robotnik also loves.

Robotnik fools Captain Rescue into capturing Sonic after the aging superhero lets his guard down, so Tails must convince Rescue to be his old self again in order to save Sonic.

Robotnik's obnoxious mother visits her son on her birthday and expects a present. After he fails to destroy a nearby forest as a present, however, she decides to capture Sonic as her own gift.

Sonic becomes the sheriff of Tranquil Gulch, in hopes of keeping Robotnik's robots from harassing the locals.

Despite the intervention of Sonic and Tails, Robotnik obtains the fourth and final emerald in prehistory. With the emeralds gathered together, Robotnik uses them to become an all-powerful being.

Robotnik sends Scratch and Grounder into space to pillage the asteroid belt, with Sonic and Tails in pursuit.

An intergalactic huntress visits Mobius, capturing various citizens and falling in love with Robotnik.

In his next time-travel stop, Robotnik plans on erasing Sonic's family tree in order to get the third emerald.

Robotnik's attempt to cause Sonic to age rapidly with his newest device backfires, turning him and Tails, and later himself, into babies.

Sonic and Tails infiltrate Robotnik's new Casino Night Zone to stop him and his henchmen from scamming a group of sheep into becoming Robotnik's slaves.

Robotnik and a rival named Brandon Quark try to cooperate in capturing Sonic. However, Sonic tricks them into becoming enemies, and they try to outdo each other.

Robotnik buys new gadgets from an enterprising salesman to help Scratch and Grounder catch Sonic, but winds up regretting his purchases when they keep backfiring.

Grounder accidentally puts a "genius chip" in his head and it makes him so smart that he easily captures Sonic and even takes over Robotnik's operations.

Sonic must save a family of sloths from Dr. Robotnik's slow-motion ray. But when he himself is slowed down by Scratch and Grounder, Tails and the sloth family must take action.

When Scratch and Grounder use Robotnik's latest invention to turn Sonic to stone, Tails attempts to foil the duo to ensure Sonic's safety.

Robotnik pursues Breezie and Robotnik Jr. in order to find out why they betrayed him with the intent of building a perpetually loyal robot wife.

Robotnik creates a robot Sonic suit in order to ruin his reputation.

Sonic tries to save a gorilla that is under Robotnik's control, while Coconuts finds the gorilla's lost baby and plots to use it against Sonic.

Tails adopts a squishy creature from another dimension named Goobster, who turns out to be a black hole.

Robotnik seemingly announces his surrender to Sonic, and he invites him to a resort in his gratitude.

Robotnik constructs a pushy robot coach in an attempt to increase Scratch and Grounder's fitness.

When Robotnik opens up a resort to make resident Mobians his slaves, Sonic enlists the help of some robots from an area of Mobius called Scrap Valley.

Robotnik imprisons a satirical cartoonist for making fun of him in his comic book, much to the chagrin of his biggest fan, Sonic.

Tails gets a megadose of Robotnik's growth gas and grows quickly to monstrous proportions, eating everything in sight and terrorizing the countryside.