Declare Genestealer Patriarch as an attacker.
Genestealer Patriarch's first ability triggers, putting an infection counter on a creature an opponent controls.
Activate Leech Bonder's ability by paying its cost, moving the infection counter from the opponent's creature onto a creature you control.
Activate Altar of Dementia by sacrificing the creature with an infection counter on it.
When the creature dies, Resourceful Defense and Genestealer Patriarch's second ability trigger.
Resolve the Resourceful Defense trigger, putting an infection counter onto another creature you control.
Resolve the Genestealer Patriarch trigger, causing you to create a token copy of the sacrificed creature that is a Tyranid in addition to its other types.
Resolve the Altar of Dementia ability.
Repeat from step 4.

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite death triggers

Infinite mill

Infinite self-mill

Genestealer Patriarch

Altar of Dementia

Leech Bonder

Resourceful Defense

Declare Genestealer Patriarch and Leech Bonder as attackers.
Genestealer Patriarch's first ability triggers, putting an infection counter on a creature an opponent controls.
Activate Leech Bonder by paying {U} and untapping it, moving the infection counter from the opponent's creature onto another creature you control.
Activate Ashnod's Altar by sacrificing the creature with an infection counter on it, adding {C}{C}.
The creature dies, triggering Resourceful Defense and Genestealer Patriarch's second ability.
Resolve the Resourceful Defense trigger, putting an infection counter onto another creature you control.
Resolve the Genestealer Patriarch trigger, causing you to create a token copy of the sacrificed creature that is a Tyranid in addition to its other types.
Repeat from step 4.

Infinite colorless mana

Ashnod's Altar

Declare Genestealer Patriarch and Leech Bonder as attackers.
Genestealer Patriarch's first ability triggers, putting an infection counter on a creature an opponent controls.
Activate Leech Bonder by paying {U} and untapping it, moving the infection counter from the opponent's creature onto another creature you control.
Activate Phyrexian Altar by sacrificing the creature with an infection counter on it, adding one mana of any color.
The creature dies, triggering Resourceful Defense and Genestealer Patriarch's second ability.
Resolve the Resourceful Defense trigger, putting an infection counter onto another creature you control.
Resolve the Genestealer Patriarch trigger, causing you to create a token copy of the sacrificed creature that is a Tyranid in addition to its other types.
Repeat from step 4.

Infinite colored mana

Phyrexian Altar

Declare Genestealer Patriarch as an attacker.
Genestealer Patriarch's first ability triggers, putting an infection counter on a creature an opponent controls.
Cast Fate Transfer by paying {1}{U/B}, moving the infection counter from the opponent's creature onto another creature you control.
Activate Ashnod's Altar by sacrificing the creature with an infection counter on it, adding {C}{C}.
The creature dies, triggering Resourceful Defense and Genestealer Patriarch's second ability.
Resolve the Resourceful Defense trigger, putting an infection counter onto another creature you control.
Resolve the Genestealer Patriarch trigger, causing you to create a token copy of the sacrificed creature that is a Tyranid in addition to its other types.
Repeat from step 4.

Combos with "Genestealer Patriarch"