The Antidote

The Antidote is a mysterious item that appears in Sonic & Knuckles: Locked and Loaded.

In Sonic & Knuckles: Locked and Loaded
Scott says that he needs to make a decision and that his life depends on it. He then pulls out a boxed game of Sonic & Knuckles as well as The Antidote. It is unknown what The Antidote solves, however, Scott ends up choosing Sonic & Knuckles because Knuckles is in it.

Trivia

 * When Scott is choosing between the two options he says "what do I take" implying that Sonic & Knuckles is some kind of medicine or cure like The Antidote.