There is evidence to show that at one point, you could play as Perci in Sonic Boom: Rise of Lyric. There’s a mission where you can either play as Amy or Knuckles. But there is a sound clip in the game’s files where Amy says “Way to go girl”. She obviously wasn’t talking to Knuckles. Now you may be saying, maybe the missing character is Sticks. There’s another voice clip where Amy says “Way to go Perci”. This implies that Perci was once playable, but the idea was scrapped, and now Perci is an NPC. That actually would’ve been cool to play as Perci. If only it were true.