The Battlefield

Blowfly Infestation

$0.30

Hapatra, Vizier of Poisons

$0.32

AI DraftFeb 26, 2026

Blowfly Infestation + Hapatra, Vizier of Poisons

Overview

When Blowfly Infestation’s triggered ability puts a -1/-1 counter on a creature, that event will cause Hapatra, Vizier of Poisons’s ability (“Whenever you put one or more -1/-1 counters on a creature…”) to trigger and create a 1/1 Snake token. If the counter(s) placed by Blowfly cause that creature to die, that death can itself cause another Blowfly trigger (Blowfly looks at last known information to check whether the dead creature had a -1/-1 counter). If Hapatra itself gets -1/-1 counters from Blowfly, Hapatra’s token-producing ability still triggers even if Hapatra’s toughness becomes 0 or less and it is put into its owner’s graveyard (see ruling) [2017-04-18].

Step 1

A creature dies; at the moment of death Blowfly Infestation’s triggered ability checks whether that creature had a -1/-1 counter on it (this uses last known information about the creature as described by rule ).

Step 2

If the condition is met, Blowfly’s triggered ability is put on the stack and, when it is put on the stack, it has a target chosen for "target creature" (targeting is chosen when the triggered ability goes on the stack; see ruling about required targeting [Ruling 2008-05-01]).

Step 3

When Blowfly’s ability resolves, it puts a -1/-1 counter on the targeted creature.

Step 4

The act of putting one or more -1/-1 counters on a creature is an event that Hapatra’s static triggered ability watches for; when you (the controller of Hapatra) put those counters on a creature, Hapatra’s ability triggers and is put on the stack ("Whenever you put one or more -1/-1 counters on a creature…").

Step 5

When Hapatra’s triggered ability resolves it creates a 1/1 green Snake token with deathtouch.

Step 6

If the -1/-1 counter(s) that Blowfly put on the target reduce that creature’s toughness to 0 or less, the creature is put into its owner’s graveyard as a state-based action .

Step 7

That death (if the creature had a -1/-1 counter on it when it died) can itself cause another Blowfly Infestation trigger to be created, and the cycle can continue.

Resolution

Blowfly’s resolved counter placement will trigger Hapatra’s "Whenever you put one or more -1/-1 counters on a creature" ability, creating a Snake token. If that placement kills the creature, the resulting death can trigger Blowfly again (Blowfly checks last known information about the creature when it died). Hapatra’s token ability still triggers even if Hapatra dies as a result of the counters put on it and per the ruling [2017-04-18]. Also note Blowfly’s ability requires a target when it triggers and must be chosen in compliance with targeting rules; see the ruling about mandatory targeting when applicable [Ruling 2008-05-01].

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