The first "Sonic the Hedgehog" game was released in 1991. It was created by Sega's Sonic Team division after Sega wanted a new mascot character. This was because they wanted to replace Alex Kidd, and they wanted to compete with Nintendo's mascot, Mario. Its success made many sequels, and it helped Sega become one of the biggest video game companies during the 16-bit era of the early 1990s. The first major 3D "Sonic" game, "Sonic Adventure", was released in 1998 for the Dreamcast.