Put a -1/-1 counter on any creature you control with toughness equal to one.
The creatue dies as a state-based action due to having zero toughness.
Nest of Scarabs and Blowfly Infestation trigger.
Resolve the Nest of Scarabs trigger, creating a creature token.
Resolve the Blowfly Infestation trigger, putting a -1/-1 counter on any creature you control with toughness equal to 1.
Repeat from step 2.

Infinite death triggers

Infinite ETB

Infinite LTB

Blowfly Infestation

Nest of Scarabs

Acftivate Carnifex Demon by paying {B} and removing a -1/-1 counter from it, putting a -1/-1 counter on each other creature.
Nest of Scarabs triggers for each counter placed this way, creating at least one 1/1 Insect creature token.
If any creatures died as a result of the counters being placed, Blowfly Infestation also triggered once for each death, putting a -1/-1 counter on Carnifex Demon and all remaining counters onto any other creature(s).
Activate Phyrexian Altar by sacrificing an Insect, adding {B}.
Repeat.

Infinite -1/-1 counters on all other creatures

Infinite sacrifice triggers

Carnifex Demon

Phyrexian Altar

Activate The Scorpion God by paying {1}{B}{R}, putting a -1/-1 counter on an X/1 creature.
The creature dies as a state-based action due to having zero or less toughness.
Blowfly Infestation and The Scorpion God trigger; target an X/1 creature with Blowfly Infestation's ability.
Resolve The Scorpion God trigger, drawing a card.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
Resolve the Blowfly Infestation trigger, putting a -1/-1 counter onto an X/1 creature.
Repeat from step 2 any number of times.
Once there are no cards in your library, end the loop by targeting a creature with more than 1 toughness with Blowfly Infestation.

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