Knollspine InvocationHow it works & interactions with other cards

Converting Cards to Damage

The core mechanic of Knollspine Invocation is its activated ability. It requires you to pay X mana and discard a card that has an identical mana value of X. This means the card's printed mana cost determines the damage dealt; you cannot overpay or underpay the X cost to change the damage output.

Resolution Step-by-Step

First, you activate the ability by choosing a value for X and a legal target. Second, you pay the mana cost of X and discard the card with mana value X as a cost. Third, the ability goes on the stack. Finally, when the ability resolves, Knollspine Invocation deals X damage to the chosen target.

Common Mistakes

One common error involves cards with X in their own mana cost. While a card is in your hand, its mana value is treated as 0 for any X in its cost. Additionally, you cannot discard a land card to this ability unless it has a mana value (lands generally have a mana value of 0). Ensure the card's mana value matches your mana payment exactly.

When to Play It

This enchantment is best used in the mid-to-late game when you have excess high-cost cards that you can't currently cast. It provides a way to use resources that would otherwise be stuck in your hand to clear the board or finish off a low-health opponent.

Interaction examples

Recycling with Breach

Underworld Breach

If you have Underworld Breach on the battlefield, you can discard a card to Knollspine Invocation to deal damage, and then potentially cast that same card from your graveyard using its escape cost. This allows you to get double the value out of every spell in your hand.

Managing the Board

Impact Tremors

While Impact Tremors deals small amounts of damage when creatures enter, it cannot target creatures to control the board. By having Knollspine Invocation active, you can discard a creature card you don't need to deal enough damage to remove an opponent's threat, supplementing your passive damage with targeted removal.