Adarkar UnicornHow it works & interactions with other cards

What It Does

Adarkar Unicorn is a creature with a activated ability that taps to produce either one blue mana {U} or one colorless and one blue mana {C}{U}. However, this mana comes with a strict restriction: it can only be used to pay for cumulative upkeep costs. This makes the Unicorn a dedicated support piece for decks running powerful but expensive maintenance-heavy permanents.

How It Resolves Step by Step

First, ensure Adarkar Unicorn is not suffering from summoning sickness and is currently untapped. During your upkeep phase, when a cumulative upkeep trigger is put onto the stack, you can activate the Unicorn's ability in response or during the resolution of the trigger. You choose whether to add {U} or {C}{U} to your mana pool. This mana exists only in your mana pool and must be spent immediately on the cost of the cumulative upkeep trigger currently being processed; if not spent, the mana will vanish as the step ends.

Common Mistakes

A frequent error is trying to use Adarkar Unicorn's mana to cast spells or pay for other types of upkeep costs, such as Echo or simple 'At the beginning of your upkeep' taxes. The restriction is specific to the keyword 'Cumulative Upkeep.' Additionally, remember that you cannot use this mana to pay for costs that occur in other phases, such as the combat phase or your main phases.

When to Play It

Adarkar Unicorn is best utilized in slower control decks that rely on cumulative upkeep cards to lock down the board or provide card advantage. Since the cost of cumulative upkeep increases every turn, the ability to generate two mana from a single source helps you keep those permanents around much longer than your land count would normally allow.

Interaction examples

Boosting Unicorn Production

Roaming Throne

If you have Roaming Throne on the battlefield with 'Unicorn' chosen as the creature type, note that Adarkar Unicorn's ability is activated, not triggered. Therefore, Roaming Throne will not cause the Unicorn to produce extra mana. You will still only get {U} or {C}{U} per tap.

Fetching Land Support

Solemn Simulacrum

While Adarkar Unicorn provides specialized mana for your upkeep, Solemn Simulacrum can enter the battlefield to find a basic Island. This ensures that even if Adarkar Unicorn is removed, you have the natural blue mana sources required to continue paying for your cumulative upkeep costs in future turns.