That's an interesting matchup! Sonic the Hedgehog is known for his incredible speed and agility, while Cuphead, from the game of the same name, is a skilled fighter with unique abilities and powerful projectiles.
If the battle is focused on speed and agility, Sonic would likely have the upper hand, as he can move at supersonic speeds and has quick reflexes. However, Cuphead's fighting skills, ability to dodge attacks, and use of different weapons and abilities could give him an advantage in a drawn-out fight.
Ultimately, it would depend on the context of the battle and the rules surrounding it. In a straightforward race, Sonic would almost certainly win, but in a combat scenario, it could go either way depending on strategy and how well each character utilizes their strengths.