Quick Answer
Grimer spawns in swamp biomes — both regular swamps and mangrove swamps are productive. It also appears in murky water-adjacent terrain and muddy areas. Grimer has no time restriction, spawning throughout the day and night. It evolves into Muk at level 38 with no special conditions. If you're specifically hunting Muk, catching Grimer and levelling to 38 is the fastest route — wild Muk is rare even in swamp biomes.
Where Grimer Spawns
Grimer's habitat is tied to wet, murky and decaying biomes. Swamps are the primary spawn zone — both the standard swamp biome with lily pads and mud, and the newer mangrove swamp biome with its dense root systems and warm shallow water. Grimer can also appear near biome boundaries where water meets muddy terrain.
There is no time restriction for Grimer — it spawns at any point in the day cycle. Simply locate a swamp biome and explore the surface terrain, particularly near water edges and muddy ground.
| Location | Biome Type | Time | Rarity | Notes |
|---|---|---|---|---|
| Swamp | Lily pads, mud, murky water | Any | Uncommon | Primary location — most consistent |
| Mangrove Swamp | Dense roots, warm shallow water | Any | Uncommon | Good density — often better than regular swamp |
| Swamp Hills | Elevated swamp terrain | Any | Rare | Less dense than flat swamps |
| Muk (wild) | Deep swamp, mangrove interior | Any | Very Rare | Evolving Grimer at 38 is much faster |
Evolution Line
Grimer's evolution into Muk is completely straightforward — reach level 38 and it evolves automatically. No items, no friendship, no special conditions.
Grimer
#0088 · Poison
Muk
#0089 · Poison
Step-by-Step Hunting Route
Find a swamp or mangrove swamp
Swamps tend to generate in lower, flatter areas with warm climates. Look for the greenish murky water and sparse dead oak trees at the surface. Mangrove swamps have warm shallow water with the distinctive mangrove root systems — check coastal and warm-climate areas.
Explore near water edges and mud
Grimer favours the edges of murky water and muddy ground rather than dry elevated terrain within the swamp. Walk along the waterline and through the muddier, lower areas for the best encounter rate.
Any time of day — no waiting needed
Unlike many Poison types, Grimer has no night restriction. Search whenever it's convenient — day or night both give the same encounter rate. This makes it one of the more accessible Poison types to hunt.
Grind to level 38 for Muk
Level 38 is the trigger — just grind Grimer to that level and it evolves automatically. Muk gains significantly improved stats, particularly HP and Attack. Consider teaching it Minimize or Acid Armor before evolving if you want a more defensive role.
Why Muk Works as a Team Anchor
Muk's 105/105 physical bulk is exceptional for a non-legendary. It shrugs off physical hits from most attackers and can survive multiple neutral attacks without healing.
Pure Poison typing means Muk can't be poisoned — useful against teams relying on Toxic. It also resists Grass, Fighting, Poison, Bug and Fairy type moves.
Beyond STAB Poison moves, Muk gets Fire Blast, Ice Punch, Thunder Punch, Shadow Ball and Explosion. This lets it threaten types that resist Poison, making it harder to wall.
FAQ
Where does Grimer spawn in Cobblemon?
Grimer spawns in swamp and mangrove swamp biomes — the murky, waterlogged terrain. It has no time restriction and appears at any time of day. Mangrove swamps often have slightly better spawn density than regular swamps.
Where does Muk spawn in Cobblemon?
Wild Muk is very rare even in swamp biomes. It appears in the deeper parts of swamps and mangrove swamps but at a much lower rate than Grimer. Catching Grimer and evolving it at level 38 is significantly faster than hunting wild Muk.
What level does Grimer evolve in Cobblemon?
Grimer evolves into Muk at level 38. No special conditions, items or moves are required — just reach level 38 and it evolves automatically.
What is Alolan Grimer and how is it different?
Alolan Grimer is a regional variant with a Poison/Dark dual typing. It has different spawn requirements (industrial-adjacent terrain rather than swamps) and evolves into Alolan Muk. If you're looking for the purple-and-black variant with a Dark secondary type, that's Alolan Grimer — not covered in this guide which focuses on standard Grimer.
Is Muk good in Cobblemon?
Yes — Muk is an underrated physical tank with 105 HP, 105 Defense and a wide movepool. Its pure Poison typing gives it useful resistances and Poison immunity. It works best as a defensive pivot or physical wall on teams that need a Grass and Fairy check.
Does Grimer only spawn at night?
No — Grimer has no time restriction in Cobblemon. Unlike many Poison types such as Gastly which are night-only, Grimer spawns throughout the day. This makes it one of the more accessible Poison types to hunt.