SegaSonic Arcade was at one point planned to be localized and released to a Western audience. Sadly, this never came about for one reason or another. However, some early localization attempts were at the very least programmed into the game. These, as well as these tiles were discovered in the arcade ROM. Arrange the tiles and you get:|
SatAM Robotnik! He doesn't appear at all in the game, so he was most likely going to be used for the western version of the game, which never came to exist.