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Rex, Cyber-Hound

Legendary Artifact Creature — Robot Dog

Whenever Rex deals combat damage to a player, they mill two cards and you get {E}{E} (two energy counters).
Pay {E}{E}: Choose target creature card in a graveyard. Exile it with a brain counter on it. Activate only as a sorcery.
Rex has all activated abilities of all cards in exile with brain counters on them.

CMC
3
Mana cost
{1}{W}{U}
Color identity
UW
Rarity
rare
Set
Fallout
Price
$0.27
EDHREC rank
#8962
Buy on TCGplayer
Rex, Cyber-Hound card art
Rex, Cyber-Hound turns every instant and sorcery cast on your turn into free card filtering, and its Pili-Pala interaction generates infinite mana without much support infrastructure. The cost — three mana for a 3/2 with no immediate board protection — is real, but the engine it enables through commanders like Dr. Madison Li makes that fragility acceptable.

Best Commanders

Commanders with the highest synergy

01
Dr. Madison Li

Dr. Madison Li

52.6% of decks · synergy 0.50

Dr. Madison Li and Rex, Cyber-Hound are a purpose-built pair — Li rewards you for casting instants and sorceries, and Rex turns those same spells into looting triggers that fuel further digging, creating a self-reinforcing spell-slinging loop.

02
Liberty Prime, Recharged

Liberty Prime, Recharged

49.1% of decks · synergy 0.46

Liberty Prime, Recharged wants artifact synergies and a high spell density, and Rex, Cyber-Hound supplies both — its artifact creature typing feeds Liberty Prime's cost reducers while the looting keeps combo and removal flowing.

03
Sophia, Dogged Detective

Sophia, Dogged Detective

30.3% of decks · synergy 0.30

Sophia, Dogged Detective rewards clue generation and graveyard interaction, and Rex, Cyber-Hound's discard-and-draw engine helps mill toward the pieces Sophia wants while keeping the hand full of action spells.

Format Analysis

Where it lives, where it can’t

FormatVerdict
commander legal
legacy legal
modern not legal
pioneer not legal
standard not legal
vintage legal
pauper not legal
oathbreaker legal

Commander is where Rex, Cyber-Hound does its real work — a repeatable loot trigger stapled to an artifact creature is exactly the kind of incremental advantage that compounds over a 100-card game. Legacy and Vintage legality is technically accurate but irrelevant; there is no competitive shell in either format that wants a three-mana 3/2 whose upside is conditional card filtering. Oathbreaker is a plausible home if your signature spell is an instant or sorcery you cast frequently, but the 20-life format moves faster and Rex dies before it generates meaningful value more often than not.

Key Combos

Combo lines featuring this card

Price Context

Current price

$0.27 bulk tier

At $0.27, Rex, Cyber-Hound is bulk — easy to pick up as a one- or two-of experiment with no financial risk. Bulk rares with genuine combo lines tend to stay in this range indefinitely, so there is no urgency either way.

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Sources

Mentioned

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Updated . Data from Scryfall, EDHREC, and Commander Spellbook.