Sewer Shambler

At the beginning of each opponent's upkeep, exile all cards from your hand face down. At the beginning of your upkeep, return all cards you own exiled with this artifact to your hand, then draw a card.

Extort (Whenever you cast a spell, you may pay W/B. If you do, each opponent loses 1 life and you gain that much life.) Whenever you tap a Swamp for mana, add an additional B.

(T: Add R or G.) As this land enters, you may pay 2 life. If you don't, it enters tapped.

Extort (Whenever you cast a spell, you may pay W/B. If you do, each opponent loses 1 life and you gain that much life.) Artifacts and creatures your opponents control enter tapped.

T: Add C. 2, T: This land becomes a copy of target land, except it has this ability.

Return up to three target land cards from your graveyard to your hand. Dredge 3 (If you would draw a card, you may mill three cards instead. If you do, return this card from your graveyard to your hand.)

Defender (This creature can't attack.) Flying Transmute 1UU (1UU, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Battalion — Whenever this creature and at least two other creatures attack, this creature gets +2/+2 until end of turn.