Blightbelly Rat — ruling 1

A player with ten or more poison counters loses the game. This is a state-based action and doesn't use the stack. In other words, it happens immediately and players can't respond to it, just like a player losing the game due to having 0 or less life.

Blightbelly Rat — ruling 2

Toxic doesn't change the amount of combat damage a creature deals. For example, if a 2/2 creature with toxic 1 deals combat damage to a player, that creature will deal 2 damage. The results of that damage are the player loses 2 life and gets a poison counter.

Blightbelly Rat — ruling 3

Any other effects of that damage, such as life gain from lifelink, still apply.

Blightbelly Rat — ruling 5

Damage dealt by a creature with toxic grants the same number of counters regardless of how much damage is dealt. Notably, if a replacement effect modifies the damage in some way (such as that of Gratuitous Violence), the number of counters given remains unchanged.

Blightbelly Rat — ruling 6

Conversely, replacement effects that apply to the number of counters put on a player can modify the counters placed this way. For example, Vorinclex, Monstrous Raider's last two abilities can apply to counters placed this way.

Blightbelly Rat — ruling 7

Multiple instances of toxic are cumulative. For example, if a creature has toxic 2 and gains toxic 1 due to another effect, combat damage that creature deals to a player will cause that player to get 3 poison counters.

Blightbelly Rat — ruling 8

To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents. You can choose any player who has a counter, including opponents. You can't choose cards in any zone other than the battlefield, even if they have counters on them.

Blightbelly Rat : règles, fonctionnement et interactions (MTG)

Blightbelly Rat is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.) When this creature dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Complete guide

Blightbelly Rat is a low-cost Phyrexian threat that exerts pressure from the moment it hits the battlefield until the moment it leaves. This creature utilizes the Toxic mechanic to poison opponents and punishes its own death by spreading even more counters across the table.

Toxic and Death Triggers

Blightbelly Rat features two distinct ways to interact with counters. First, its Toxic 1 ability ensures that any combat damage dealt to a player results in that player receiving a poison counter in addition to the life loss. Second, it has a triggered ability that occurs when it dies, allowing you to Proliferate. This means you can add an extra counter to any number of permanents or players that already have at least one counter of any kind.

Resolving Proliferate

When Blightbelly Rat dies, the proliferate ability is put on the stack. Upon resolution, you choose any number of players and/or permanents. For each one chosen, if they have counters, you add one more of every type they already possess. If a player has both an energy counter and a poison counter, choosing them adds one of each. Note that this selection happens during resolution, so opponents cannot wait to see what you choose before deciding to respond; they must respond while the ability is still on the stack.

Common Misconceptions

A common mistake is thinking Toxic 1 changes the amount of damage dealt; it does not. A 2/2 with Toxic 1 still deals 2 damage and reduces the opponent's life by 2. Another important detail is that Toxic only applies to combat damage dealt to players. If Blightbelly Rat deals damage to a creature or planeswalker, or if it deals noncombat damage, no poison counters are generated.

Strategy and Timing

Blightbelly Rat is best utilized in aggressive decks that aim to win through Poison Counters. Because its death trigger helps you Proliferate, it is an excellent candidate for blocking or being used as sacrifice fodder. Even if your opponent manages to kill it, they may inadvertently help you reach the ten-poison-counter threshold required to win the game.

Interaction examples

The First Sting

Blightbelly Rat

Poison Counter

Blightbelly Rat attacks and is not blocked. It deals 2 combat damage to the opponent. The opponent loses 2 life and, because of Toxic 1, they also receive one Poison Counter. The total damage dealt remains 2 regardless of the toxic value.

Death and Decay

Blightbelly Rat

Blood Artist

You have a Blood Artist and a Blightbelly Rat on the battlefield, and your opponent already has a poison counter. When Blightbelly Rat dies, both its ability and Blood Artist's ability trigger. You can stack them so Blood Artist resolves first, draining 1 life, then the Rat's proliferate trigger resolves. You choose the opponent to receive another poison counter, bringing their total to two.

Blocking Choices

Blightbelly Rat

Ornithopter of Paradise

If your opponent blocks Blightbelly Rat with Ornithopter of Paradise, the Rat deals 2 damage to the creature and the Ornithopter deals 0 damage to the Rat. Because the Rat dealt combat damage to a creature rather than a player, the Toxic 1 ability does not trigger, and no poison counters are given to the opponent.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Blightbelly Rat

Original English text — Wizards of the Coast / Scryfall

#1February 4, 2023· Wizards of the Coast
A player with ten or more poison counters loses the game. This is a state-based action and doesn't use the stack. In other words, it happens immediately and players can't respond to it, just like a player losing the game due to having 0 or less life.
Card named in this ruling
Poison Counter
#2February 4, 2023· Wizards of the Coast
Toxic doesn't change the amount of combat damage a creature deals. For example, if a 2/2 creature with toxic 1 deals combat damage to a player, that creature will deal 2 damage. The results of that damage are the player loses 2 life and gets a poison counter.
Card named in this ruling
Poison Counter
#3February 4, 2023· Wizards of the Coast
Any other effects of that damage, such as life gain from lifelink, still apply.
No other card is named in this ruling.
#4February 4, 2023· Wizards of the Coast
If a creature with toxic deals combat damage to a creature or planeswalker, or if it deals noncombat damage, toxic has no effect and no player gets poison counters.
Card named in this ruling
Poison Counter
#5February 4, 2023· Wizards of the Coast
Damage dealt by a creature with toxic grants the same number of counters regardless of how much damage is dealt. Notably, if a replacement effect modifies the damage in some way (such as that of Gratuitous Violence), the number of counters given remains unchanged.
No other card is named in this ruling.
#6February 4, 2023· Wizards of the Coast
Conversely, replacement effects that apply to the number of counters put on a player can modify the counters placed this way. For example, Vorinclex, Monstrous Raider's last two abilities can apply to counters placed this way.
No other card is named in this ruling.
#7February 4, 2023· Wizards of the Coast
Multiple instances of toxic are cumulative. For example, if a creature has toxic 2 and gains toxic 1 due to another effect, combat damage that creature deals to a player will cause that player to get 3 poison counters.
Card named in this ruling
Poison Counter
#8February 4, 2023· Wizards of the Coast
To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents. You can choose any player who has a counter, including opponents. You can't choose cards in any zone other than the battlefield, even if they have counters on them.
No other card is named in this ruling.
#9February 4, 2023· Wizards of the Coast
You don't have to choose every permanent or player that has a counter, only the ones you want to add another counter to. Since "any number" includes zero, you don't have to choose any permanents at all, and you don't have to choose any players at all.
No other card is named in this ruling.
#10February 4, 2023· Wizards of the Coast
If a player or permanent has more than one kind of counter on it, and you choose for it to get additional counters, it must get one of each kind of counter it already has. You can't have it get just one kind of counter it already has and not the others.
No other card is named in this ruling.
#11February 4, 2023· Wizards of the Coast
An ability that triggers "Whenever you proliferate" triggers even if you chose no permanents or players while doing so.
No other card is named in this ruling.
#12February 4, 2023· Wizards of the Coast
Players can respond to a spell or ability whose effect includes proliferating. Once that spell or ability starts to resolve, however, and its controller chooses which permanents and players will get new counters, it's too late for anyone to respond.
No other card is named in this ruling.
#13February 4, 2023· Wizards of the Coast
If a permanent ever has both +1/+1 counters and -1/-1 counters on it at the same time, they're removed in pairs as a state-based action so that the permanent has only one of those kinds of counters on it.
No other card is named in this ruling.