Progenitor Mimic + Time Stretch + Eternal Witness

3-card combo · GU

Verdict

Yes — this 3-card loop chains infinite extra turns through Progenitor Mimic's upkeep trigger recurring Time Stretch every turn.

Cards required: 3
Cheapest stack total: $9.45
Color identity: GU
Popularity: 76 decks
Format: Commander

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Progenitor Mimic copying Eternal Witness is the engine: each upkeep it creates a new Eternal Witness token, which enters and immediately returns Time Stretch from the graveyard to hand. Cast Time Stretch for 10 mana, take two extra turns, and the loop restarts — the table never untaps again. Simic shells running Biovisionary or The Mimeoplasm already want Progenitor Mimic and Eternal Witness together, making this a natural fit.

Recipe

How it works

Prerequisites

Progenitor Mimic is a copy of Eternal Witness.

Steps

Cast Time Stretch by paying , taking two extra turns after this one.
At the beginning of your next upkeep, Progenitor Mimic triggers, creating a token copy of Eternal Witness.
When the token Eternal Witness enters the battlefield, it triggers itself, returning Time Stretch from your graveyard to your hand.
Repeat.

Result

Infinite turns; Lock

Variations

Cheaper, tighter, alternate lines

Strionic Resonator can copy the Mimic's upkeep trigger for redundancy, though that adds a fourth piece. The combo needs 10 mana available every loop, so any response that counters or exiles Progenitor Mimic before the upkeep trigger resolves collapses the whole line — protect it with Swiftfoot Boots or Veil of Summer. Walk the Aeons is a cheaper stand-in for Time Stretch if the goal is just locking turns, but it requires sacrificing Islands to recur naturally.