How to evolve Grimer in Cobblemon.
Grimer evolves into Muk when it reaches level 38.
Evolution line
Grimer→
Muk
MukWhat Grimer needs
1 pathMukLevel up
Level 38
Moves it learns on evolving
Venom Drench
These are offered the moment the evolution completes. Decline them and you have to relearn them later.
Is it worth it
Grimer nowpoison325
Mukpoison500
Base stat totals, from the Cobblemon 1.7.3 species files.