User blog comment:SilverPlays97/12 Days of SNN: Day 7/@comment-477304-20131219180519/@comment-1986314-20131219181409

It's listed in the credits, but I'll reiterate:

A guy named "Unstoppablesthombo" made the Eggman Sprites. I couldn't find any that I liked on the Mystical Forest Zone, so I did a little bit of searching on Google, and found the current sprites.