Prototype in MTG: Rules, FAQ, and Best Cards

Last updated on March 19, 2024

Arcane Proxy | Illustration by Kekai Kotaki

Who doesn’t love the idea of monstrous magic-imbued robots clashing on a war-strewn battlefield? Mech fans rejoice, there’s a Magic mechanic that embodies everything you love about the robot-on-robot clashes of properties like Transformers, Pacific Rim, and Gundam. And it’s got such a fitting name.

That’s right, this mechanic is The Brothers’ War’s prototype. I’ll be your resident robot-loving L1 judge here to answer any questions about how to cast your prototype creatures and how they behave in different game zones.

Ready? Let's get into it!

How Does Prototype Work?

Hulking Metamorph | Illustration by Diego Gisbert

Prototype is an additional option you have when casting a spell. You can cast a prototype creature for its normal casting cost in the top right of the card, or you can cast it for its prototype cost in the text box.

If you choose the prototype cost, the attributes of the card change. It has a different power, toughness, and mana cost, and the color of the card also changes. All other abilities remain the same regardless of which cost you choose to pay.

Here's the golden rule for understanding when you can and can’t use the prototype cost: if you aren’t casting the creature, prototype can’t be used.

Is Prototype an Activated Ability?

Prototype isn’t an activated ability but a static ability that provides a different possible casting cost for your creature. Pithing Needle, for example, won’t stop your opponent from casting a creature for its prototype cost.

Is Prototype an Alternate Cost?

Not precisely, because an alternate cost can still be applied to whichever prototype cost you choose. But functionally, it plays similarly to alternate casting costs just like evoke or blitz. You choose which set of characteristics the card has when you cast it. The prototype cost always results in less power, toughness, and mana cost.

What's the Mana Value of a Prototyped Card on the Stack?

If you paid the prototype cost of a spell on the stack, that card has a mana value associated with the prototype cost. For example, if you cast Combat Thresher for its prototype cost then the spell will have a mana value of three.

What's the Mana Value of a Prototyped Card in Play?

The mana value of a prototyped card carries over once that permanent is in play. Paying the prototype cost of a card changes its physical mana cost, so you use that new mana cost to determine the mana value.

What Color Is a Prototyped Card in Play?

You can tell which color a prototype creature becomes by the mana symbols in its prototype cost. They’re always colorless cards in your hand but are treated as their new color if you pay the prototype cost.

If you pay to cast Skitterbeam Battalion, it’s a red spell on the stack and a red permanent in play.

I should mention the color identity of prototype cards as it relates to Commander. All prototype creatures are colorless by default, but their color identity includes their prototype colors. Arcane Proxy, for example, has a blue color identity and can only be played in blue Commander decks.

When You Prototype Is it an Artifact Spell?

Prototype only exists on artifact creatures, and those spells remain artifacts whether their prototype cost was paid or not. The prototype reminder text says “it keeps its abilities and types,” meaning the artifact part of the card never changes.

What Are the Color and Mana Value of a Prototype Card in the Graveyard?

Prototype cards in graveyards are colorless and have their normal mana values. Remember that golden rule: prototype is irrelevant if you aren’t casting the card. If you’re just looking at the card's characteristics in another zone then you can ignore the prototype text.

Can You Prototype a Card if You Reanimate It?

Generally, no. Normal reanimation spells won’t allow you to pay the prototype cost for a card. Reanimation effects don’t generally ask you to cast the reanimation target, they just put the card from the graveyard onto the battlefield. If that’s the case then there’s no opportunity for you to pay an alternate casting cost like prototype.

Can You Prototype if You Cast from the Graveyard?

If a spell or ability lets you specifically cast a creature from a graveyard, you can choose to cast it for its prototype cost. But if the effect specifies that you can cast that card without paying its mana cost, you can’t choose the prototype cost.

For example, the effect on Rivaz of the Claw allows you to cast Fallaji Dragon Engine from your graveyard for either its normal cost or its prototype cost. But a card like Wondrous Crucible won’t allow you to pay an alternate casting cost like prototype.

What Happens If You Blink a Prototype?

When you blink a prototype creature it re-enters the battlefield with all its normal non-prototype characteristics. Even if you paid the prototype cost the first time you cast it, blinking it “resets” everything and you’re left with the bigger colorless version of the card.

What's the Point of Prototype?

Prototype exists to flesh out the themes of The Brothers’ War. The set revolves around the conflict between Urza and Mishra, who both command armies of machines to wage war against each other. These prototype creatures represent the destructive robotic forces of that war.

From a design standpoint, prototype is a great way to reward players for playing ramp strategies with giant game-ending threats. They provide mana sinks for the Powerstone token producing cards in BRO while having a cheaper alternate cost that makes them more tenable for Limited.

Is Prototype Good?

Prototype is definitely great for Limited, and a few heavy hitters have a chance to see more play in Constructed formats. Mechanics that offer flexibility usually see play somewhere, even if that means you only see these cards in Commander.

It may not be a tier 1 strategy, but players brew around the idea of blinking and reanimating prototype creatures to “cheat” on their more expensive halves. I think of prototype as one of the defining features of The Brothers War Limited and is due for a bigger splash in Standard.

Gallery and List of Prototype Cards

There are 20 prototype creatures in Magic, 17 from the main The Brothers's War set, two from Alchemy: The Brother's War and another from the supplementary Jumpstart set for BRO.

• Rootwire Amalgam
• Autonomous Assembler
• Arcane Proxy
• Skitterbeam Battalion
• Steel Seraph
• Spotter Thopter
• Hulking Metamorph
• Iron-Claw Crusher
• Phyrexian Fleshgorger
• Fallaji Dragon Engine
• Combat Thresher
• Rust Goliath
• Depth Charge Colossus
• Woodcaller Automaton
• Goring Warplow
• Blitz Automaton
• Boulderbranch Golem
• Cradle Clearcutter
• Warzone Duplicator
• Forgefire Automaton

Best Prototype Cards

The recursion at no extra cost makes Forgefire Automaton ripe for value in sacrifice engines. There are plenty of cards that weren't designed to have 3 power, much less 8, but Forgefire will give it to them anyway. If you were confused about prototype cards at first, don't be, this one is simply powerful and worth a mythic wildcard.

The Warzone Duplicator lets you play with your opponent's cards in a fair way. Alchemy players get your creative juices flowing, as copying nontoken creatures leads to lots of shenanigans.

Arcane Proxy looks to be one of the standout prototype cards for Constructed. It mimics the effects of cards like Snapcaster Mage and Torrential Gearhulk, which were Standard powerhouses.

Phyrexian Fleshgorger also has a strong chance of seeing Standard play. It plays the role of an aggressive 3-drop very well and also makes for a powerful reanimation or blink target. With Touch the Spirit Realm in Standard it’s only a matter of time before someone brews a deck that looks to blink a 7/5 Fleshgorger into play early in the game.

Autonomous Assembler and Steel Seraph have decent stats and abilities for Standard, but they might miss the mark.

Rootwire Amalgam can also make a big token. Like, big. Sometimes that’s enough to see play with the right supporting pieces.

Decklist: Prototype in Standard

Phyrexian Fleshgorger | Illustration by Steve Prescott

I’ve provided a pretty tame outline of what a Standard control deck might look like if it tried to slot in the new prototype creatures. The idea here is to use Fake Your Own Death or a blink effect to reset your prototype creatures.

Touch the Spirit Realm is the best version of this effect in Standard, but Planar Incision has some janky combo potential with Arcane Proxy.

Wrap Up

Woodcaller Automaton | Illustration by Ryan Pancoast

I’m with the rest of the Magic community when I say the prototype mechanic is fantastic. It is too early to tell whether it has a lasting impression in Constructed or not, it is one of the most memorable aspects of The Brothers' War Limited. There’s no denying that casting giant robots and war-mechs is Magic at its most exciting.

If the positive feedback is any indication then we can expect to see this mechanic again in the future. It might require the right fantasy setting to make sense but I’m confident more prototype cards will appear down the line.

Have you tried prototype in Magic? Got any burning questions I didn’t cover here? Let me know in the comments or over on the Draftsim Discord.

I hope I’ve answered any of your questions about the mechanic, and I love seeing how players cheat their giant battlecruiser creatures into play!