Underworld Breach + Stitcher's Supplier + Phyrexian Altar

Powerful

1,761

Decks

How it works

—

Activate Phyrexian Altar by sacrificing Stitcher's Supplier, adding .
Stitcher's Supplier dies, causing you to mill three cards.
Cast Stitcher's Supplier for its escape cost by paying and exling three other cards from your graveyard.
Stitcher's Supplier enters the battlefield, causing you to mill three cards.
Repeat.

In which brackets is this combo allowed, per Spellbook's Powerful tier?

1–2 · Exhibition & Core

Spellbook classifies this as Powerful — not for these brackets.

3 · Upgraded

Allowed in this bracket.

4–5 · Optimized & cEDH

All combos are allowed.