whoneedsnamestbh
Eye of Cthulhu
The difference is that Eye of Cthulhu has nothing else to attack you with when it chain dashes meaning you can run away in one direction while with Spazmatism you have to worry about Retinazer’s attacks.That's just untrue. It's objectively better.
Unless of course you kill Retinazer first, but I usually kill Spazmatism first anyway because second phase Spaz + first phase Ret is much more manageable than the other eay around.