Sega has since released a teaser image (above) along with the following caption: "Six will rise from the Lost World. Are they friends or foes? Find out on May 29th."
Do any of these characters look familiar to you? I must confess, I'm no Sonic aficionado, so my brain is virtually of no use in solving this puzzle. Sega fans, be sure to sound off with your guesses in the comments below.