Sega

Sega is a video game company. The mascot of Sega is Sonic the Hedgehog, though it used to be Alex Kidd until 1991. In the past, Sega used to be the rival company of Nintendo. Both companies made fun of the other company's mascot many times.

An early mockery happened in Alex Kidd's final game, Alex Kidd in Shinobi World. The first boss was originally going to be named Mari-Oh, a parody of Mario, however, it was changed to Kabuto (this name was later been used on a Pokémon). There are also characters called the "Marxio Brothers" in Sonic the Comic, a British comic.

To counter these mockeries of Mario, Rare had Sonic and Earthworm Jim make "cameo appearances" in Donkey Kong Country 2: Diddy's Kong Quest. Although they apparently joined Cranky Kong's contest of collecting DK Coins, Sonic and Jim apparently did not succeed in getting many coins. Neither ranked third place, and the pair seemed to have fled from Mushroom World. Sonic left his shoes behind when he left and Earthworm Jim left behind his blaster, both of which were put by a trash can, and labeled "No Hopes". Another (possible) mockery is the Harry Hedgehog enemy in Super Mario World 2: Yoshi's Island. Its blue coloration and rather quick moving pace may have been a mockery of Sonic; however, this may have been a coincidence.

This feud lasted for many years, until Sega became a third-party developer in 2002, with the closing of their console-producing division. Sonic Adventure 2: Battle, appeared on the Nintendo GameCube for the first game ever. Their first effort by teaming up with Nintendo resulted in F-Zero AX/GX. The two companies later teamed up to create a crossover game featuring both Mario and Sonic, Mario & Sonic at the Olympic Games and Mario & Sonic at the Olympic Winter Games. Sonic also appeared in Super Smash Bros. Brawl.

Mario Games developed by Sega

 * Mario & Sonic at the Olympic Games - Wii, 2007; Nintendo DS, 2008
 * Mario & Sonic at the Olympic Winter Games - Wii, 2009; Nintendo DS

Mario Games published by Sega

 * Mario & Sonic at the Olympic Games (in North America and Europe only)
 * Mario & Sonic at the Olympic Winter Games (in North America and Europe only)