Infinite ETB, Infinite LTB, Infinite Mutagen tokens, Infinite death triggers, Infinite mill, Infinite sacrifice triggers, Infinite self-mill, Infinite storm count
Cast Metalwork Colossus by paying , which enters with at least two +1/+1 counters on it due to Arwen.
Activate Altar of Dementia by sacrificing Metalwork Colossus.
When Metalwork Colossus dies, The Ooze triggers, creating a Mutagen token for each +1/+1 counter Metalwork Colossus had.
Resolve the Altar of Dementia ability.
Activate Metalwork Colossus by sacrificing two Mutagens, returning it from your graveyard to your hand.
Repeat.
Component Cards
How It Works
Cast Metalwork Colossus by paying , which enters with at least two +1/+1 counters on it due to Arwen.
Activate Altar of Dementia by sacrificing Metalwork Colossus.
When Metalwork Colossus dies, The Ooze triggers, creating a Mutagen token for each +1/+1 counter Metalwork Colossus had.
Resolve the Altar of Dementia ability.
Activate Metalwork Colossus by sacrificing two Mutagens, returning it from your graveyard to your hand.
Repeat.