Chaos

Realize the godly power of Perfect Chaos:

Why is shadow there?

It's a giant eel!!!!

The person decided to put Shadow in the artwork along with Sonic and Chaos in their artwork, that's why he's in it. Do you think tha fighting Perfect Chaos the second time was a little harder than the first time?

I found neither hard, if I am being honest.

I can't think of a hard Sonic boss.

Metal Madness/Overlord takes along time, but he is not hard, the hardest boss was the giant eggman from STH2.