Master Emerald (InstanceTopic, 8)
From Compile Worlds
The Master Emerald is a key item in the Sonic series. It first appears in Sonic 2 Beta, but was retconned as a mere pipe blocker (though that's one expensive-looking pipe blocker if I may say so myself). More importantly, it appears in Sonic 3 & Knuckles and Sonic Adventure 2, where Knuckles (supposedly) guards it.
