Geometer's Arthropod
Creature — Fractal Crab
Whenever you cast a spell with 
in its mana cost, look at the top X cards of your library. Put one of them into your hand and the rest on the bottom of your library in a random order.
- CMC
- 2
- Mana cost
- Color identity
- GU
- Rarity
- rare
- Set
- Secrets of Strixhaven
- Price
- $0.33
- EDHREC rank
- #14613
Geometer's Arthropod puts a power-and-toughness doubling effect on the board the turn it enters, and in the right shell that means every X-spell or counter-stacking payoff immediately becomes twice as threatening. The cost is real — five mana for a creature that does nothing without a critical mass of +1/+1 counters already in play — but Zimone, Infinite Analyst lists include it at nearly a 49% rate because that critical mass is exactly what those decks manufacture.
Best Commanders
Commanders with the highest synergy
Zimone, Infinite Analyst
Zimone, Infinite Analyst is the canonical home: her engine floods the board with +1/+1 counters, and Geometer's Arthropod converts that resource directly into lethal combat math without needing any additional setup.
Magus Lucea Kane
Magus Lucea Kane copies X-spells, and Geometer's Arthropod makes every creature that benefits from those spells hit twice as hard — the doubling effect compounds with Kane's copy triggers to close games fast.
Zaxara, the Exemplary
Zaxara, the Exemplary generates Hydra tokens sized by X-spell costs, and Geometer's Arthropod instantly doubles those tokens' stats, turning a board of medium Hydras into an overwhelming alpha strike.
Primo, the Unbounded
Primo, the Unbounded proliferates aggressively, and Geometer's Arthropod rewards each proliferate trigger by making the growing creature base proportionally larger, accelerating the deck's path to a winning board state.
Format Analysis
Where it lives, where it can’t
| Format | Verdict |
|---|---|
| commander | legal |
| legacy | legal |
| modern | legal |
| pioneer | legal |
| standard | legal |
| vintage | legal |
| pauper | not legal |
| oathbreaker | legal |
Geometer's Arthropod is a Commander card through and through — the +1/+1 counter synergies it rewards are a Commander-specific archetype, and five mana for a conditional doubling effect only pays off in a format where you have the turns and the board to support it. In competitive 60-card formats like Modern and Pioneer, it's strictly unplayable: five mana buys you a win condition, not a scaling enabler that depends on prior setup. Standard legality is academic unless a dedicated counter-stacking shell exists in the format at the time, and even then the power ceiling is low outside multiplayer. Legacy and Vintage have no use for it whatsoever.
Key Combos
Combo lines featuring this card
Price Context
Current price
$0.33 bulk tier
At $0.33, Geometer's Arthropod sits firmly in bulk territory, which is accurate given its narrow application outside counter-based Commander decks. It's a safe pickup for the archetypes that want it — no price risk, no reason to hesitate — but don't expect that to change; bulk rares with format-specific utility tend to stay bulk.
Explore
Sources
Updated . Data from Scryfall, EDHREC, and Commander Spellbook.