User blog comment:Slug-Drones/Sonic Generations - Info (does not contain official announcements) *Possible Spoilers*/@comment-3437898-20110921033304

In addition to what you said about Sky Sanctuary,tThere is also that picture with a purple Eggrobo model on the wiki. Correct me if I'm wrong but didn't they only appear in Sky Sanctuary Zone (excluding Knuckles boss battles).