KyoKusanagi said:
You forget that the original Dragonball series was out in the 1970s and that Dragonball Z was out in the 1980s well before Sonic the Hedgehog was even a twinkle in Sega's eye.
DragonBall originally aired in Japan on February 26th, 1986 and ended April 19th, 1989.
DragonBallZ originally aired in Japan on April 26th, 1989 and ended January 31st, 1996.
DragonBallGT, the animated fanfic garbage, originally aired in japan on February 7th, 1996 and ended November 21st, 1997.
Just so you know.
Edit:
Sonic 2 was the first sonic game to feature Super Sonic, and it came out:
Sonic the Hedgehog 2 Sega 11/20/92 North America
Sonic the Hedgehog 2 Sega 11/21/92 Japan
Goku goes SSJ for the first time on (Japanese) episode 95,
Son Goku Becomes the Legendary Super Saiya-jin!
95 episodes, at one week each equals 665 days, or 1.8219178082191780821917808219178 years..
Meaning the original airing of DBZ of April 26th, 1989, plus 665 days would be..
Goku first went SSJ in Japan on March 28th, 1991. Assuming they didn't skip any weeks.
And not to mention SSJ would've been in the manga a little before the anime.
That gave them about a year and a half to "borrow" the idea and put it in the Sonic games.