The whole gimmick for Sonic12's "Hole" appearance is like how a black hole works. With everything being stretched and absorbed inside the center. It's.... "Where nothing can escape the gravitation pull it just somehow pulls off. You better not get inside the hole or your body stretches like hell and it’s vastly painful. If you’re in the hole, then you're inside Sonic12... and seeing the inside of it’s true form would break your mind, so SOME victims close their eyes and try to block off the voices inside. Eventually, it’ll either spit you out or will simply erase your very existence if you become so boring to play. It only does that with only its hole appearance by choice."

There's also the three digit fingers, which can easily make it penetrat through anything; whether it be soft, hard, or said to be impenetrable.

The downside to this form is that it limits Sonic's expression and speaking. It also wouldn't let it to see, but what's the point of eyes if you know what you're looking at.

Sonic doesn't use this design for SONIC12, but for a different game... SONIC B-DEVILD... sounds cool right?