Mana CannonsHow it works & interactions with other cards

Unpacking the Trigger

The ability of Mana Cannons is a triggered ability that goes on the stack whenever you cast a multicolored spell. For the purpose of this card, a spell is multicolored if it has two or more colors. The amount of damage dealt, represented by X, is determined by the specific number of colors in that spell's color indicator or mana cost. For example, a Red and Green spell will deal 2 damage, while a five-color spell will deal 5 damage.

The Casting Process

First, you must announce the multicolored spell and pay its costs. Once the spell is officially 'cast', Mana Cannons triggers and you choose a target for the damage (a player, planeswalker, or creature). This trigger goes on the stack on top of the spell that caused it. This means the damage will resolve before the spell itself actually enters the battlefield or takes effect.

Common Pitfalls

A common mistake is thinking Mana Cannons counts the number of colors among permanents you control; it only cares about the colors of the single spell currently being cast. Additionally, colorless spells or spells with only one color will not trigger the ability at all. If the target of the damage trigger becomes illegal before the ability resolves, no damage is dealt, but the original spell will still resolve as normal.

When to Deploy

Mana Cannons is best played early in a deck built around gold cards to maximize the number of triggers. Since it triggers 'on cast', it is particularly effective against counterspells; even if your opponent counters your multicolored creature or sorcery, the Mana Cannons damage trigger has already been placed on the stack and will still resolve.

Interaction examples

Multi-Layered Enchantment Pressure

Impact Tremors

If you have both Mana Cannons and Impact Tremors on the battlefield and cast a multicolored creature spell like a Red/White soldier, Mana Cannons triggers immediately upon casting to deal 2 damage to any target. After that resolves and the creature successfully enters the battlefield, Impact Tremors triggers to deal 1 damage to each opponent. This allows you to pick off a small creature and chip away at your opponent's life total with a single card play.

Escaping the Graveyard

Underworld Breach

With Underworld Breach on the field, cards in your graveyard gain escape. If you cast a multicolored spell from your graveyard using the escape mechanic, Mana Cannons recognizes this as a spell being cast. You will still get the damage trigger based on that spell's colors, allowing you to reuse your gold spells as repeated ammunition for the Cannons.