False Alarms/TV Watermark
From Sonic Retro
Green Object in Hidden Palace
Source: Unknown French magazine
At the first glance this picture looks pretty normal. But look closer and you'd notice the green object above the life icon.
Some people said it looks like a statue or rock in the background. The green colour surely blends in nicely with the rest of Hidden Palace.
adamis at the message board pointed out it's nothing but a watermark logo on the TV. Here are two other screenshots adamis attached:The exact same object appears at the exact same location on the screen. Without any doubt, the green object in the HPZ picture is definitely not part of the game.
Case closed.