.......... Parasite Vs Grundy ..........

Who wins?
No prep..

Parasite

Vs

Solomon Grundy

Parasite more than not if he gets to drain him.
Grundy more than not if he takes him out from a distance.

ummm what version of Grundy... the guy has probably closer to 10 or so distinctly identifiable incarnations.
Grundy that Batman can contend with.
Smart Grundy
Stupid Brute Grundy on his average strength
PC level Grundy who stomped on preDCNU Supes

Grundy Smash

Smart Grundy

DCnU Grundy or Pre-Flashpoint?

Pre

Parasite