Robotnik with Wolverine claws. Best.

Looking back, we can scratch off 6 (Image Comics and Megaman crossovers),
4 (issue 25 had a silver foil cover, as well as Sonic Universe #25),
2 (no movie was made, the OVA is dubious if it counts, but supposedly a live action movie was proposed by Sega recently)
and 1 (Sonic “died” at least two occasions; 20 and 125) off this list :P

Also; I just realized one of Robotnik’s left fist has his thumb on the wrong side.