Sludge Monster
Creature — Horror
Whenever this creature enters or attacks, put a slime counter on up to one other target creature.
Non-Horror creatures with slime counters on them lose all abilities and have base power and toughness 2/2.
- CMC
- 5
- Mana cost
- Color identity
- U
- Rarity
- rare
- Set
- Innistrad: Midnight Hunt Promos
- Price
- $0.67
- EDHREC rank
- #3823
Sludge Monster locks down every creature its slime counters touch, turning the board into a parade of 0/1 Oozes and stripping away abilities that would otherwise threaten you. The cost — five mana for a 4/4 that only sticks counters on attack — means it rewards decks that can protect it and punish decks that can't leverage the slowdown. Toxrill, the Corrosive turns those slime counters into a kill condition, which is the version of this card you actually want to be playing.
Best Commanders
Commanders with the highest synergy
Toxrill, the Corrosive
Sludge Monster's slime counters feed directly into Toxrill, the Corrosive's engine — each end step, Toxrill destroys every creature carrying one, then converts the deaths into 1/1 Slug tokens and lets you sacrifice those for card draw. The two cards share a self-reinforcing loop that forms the core identity of Toxrill lists.
Captain N'ghathrod
Captain N'ghathrod mills opponents and then steals what hits the graveyard, and Sludge Monster makes sure the creatures still on the battlefield can't stop the assault — stripping abilities and shrinking them to 0/1s clears the way for N'ghathrod's Horror tribal attackers. The tempo swing from nullifying blockers is exactly what a theft-and-mill strategy needs.
Umbris, Fear Manifest
Umbris, Fear Manifest grows every time an opponent exiles cards, and Sludge Monster stalls opposing boards long enough to make that growth matter by neutralizing creatures that would otherwise race or block Umbris down. The Horror subtype is a bonus in tribal builds that care about the creature type.
Niko, Light of Hope
Niko, Light of Hope generates Shard tokens and cares about creatures entering the battlefield, and Sludge Monster's repeated slime-counter placement on attackers creates a steady stall that lets Niko's lifegain and token engines grind out value safely. The synergy is looser than the blue-black pairings but the defensive ceiling is real.
Kros, Defense Contractor
Kros, Defense Contractor hands out counters to opponents' creatures to goad them, and Sludge Monster's slime counters ensure those goaded creatures are 0/1s with no abilities when they attack into your opponents. The combination weaponizes your opponents' boards against each other while leaving you largely untouched.
Format Analysis
Where it lives, where it can’t
| Format | Verdict |
|---|---|
| commander | legal |
| legacy | legal |
| modern | legal |
| pioneer | legal |
| standard | not legal |
| vintage | legal |
| pauper | not legal |
| oathbreaker | legal |
Sludge Monster is a Commander card — the ability to repeatedly neuter entire boards scales with the number of opponents, and multiplayer gives it time to accumulate counters that would be too slow in a one-on-one game. In Legacy, Modern, and Pioneer it's strictly too expensive for what it does; a five-mana 4/4 that doesn't win the game immediately gets outpaced by formats built around efficiency. Oathbreaker shares enough of Commander's multiplayer math that Sludge Monster is at least functional there, particularly in blue-black stax-adjacent shells. Play it in Commander, ignore it everywhere else.
Key Combos
Combo lines featuring this card
Price Context
Current price
$0.67 bulk tier
At $0.67, Sludge Monster is bulk — easy to acquire and unlikely to drop meaningfully lower given its 77% inclusion rate in Toxrill, the Corrosive decks. It won't appreciate, but there's no reason to wait on a card this cheap that fills a clear role.
Explore
Sources
Mentioned
- Toxrill, the Corrosive
- Captain N'ghathrod
- Umbris, Fear Manifest
- Niko, Light of Hope
- Kros, Defense Contractor
Updated . Data from Scryfall, EDHREC, and Commander Spellbook.