Thorn of AmethystHow it works & interactions with other cards

What it Does

Thorn of Amethyst applies a static ability that increases the cost of casting any noncreature spell by {1}. This effect applies to all players, including you. It affects artifacts, enchantments, instants, sorceries, and planeswalkers, regardless of their original mana cost or whether they are being cast for an alternative cost.

How it Resolves Step by Step

When a player attempts to cast a noncreature spell, the total cost is determined before it is paid. First, the mana cost or alternative cost is set. Second, all cost increases (like the one from Thorn of Amethyst) are applied. Third, cost reductions are applied. Finally, effects like Trinisphere are applied if applicable. Once the final total is calculated, the player pays the mana to complete the casting process.

Common Mistakes

A frequent error is assuming Thorn of Amethyst affects creature spells that have additional noncreature types, such as Artifact Creatures or Enchantment Creatures. However, the game checks if the spell has the 'Creature' type; if it does, the tax does not apply. Additionally, remember that this tax applies to every noncreature spell, even if you are casting it for 'free' via another effect, as the {1} tax is added to that alternative cost of zero.

When to Play It

This card is most effective in decks that feature a high density of creature spells, often referred to as 'Hatebears' or 'Stax' strategies. It is particularly potent against combo decks or control decks that need to chain multiple low-cost spells like mana rocks or cantrips to achieve their goals.

Interaction examples

Taxing Mana Rocks

Sol Ring

If Thorn of Amethyst is on the battlefield and you want to cast Sol Ring, you must pay {1} (its mana cost) plus {1} (the tax). The total cost to cast Sol Ring becomes {2}.

Multiplying the Burden

Arcane Signet

When you attempt to cast Arcane Signet while Thorn of Amethyst is present, the game identifies Arcane Signet as a noncreature spell. You must pay {2} for the mana cost and an additional {1} for the tax, totaling {3} mana.