Thassa's InterventionHow it works & interactions with other cards

Dual Purpose Versatility

This spell offers two distinct modes: a card-selection tool or a powerful tax-based counterspell. When you cast Thassa's Intervention, you must choose which mode you are using before paying costs. The value of X determines both how many cards you look at or how much mana your opponent must pay to save their spell.

Resolving the Selection Mode

If you choose the first mode, you look at the top X cards of your library. You can choose to put zero, one, or two of those cards into your hand. The remaining cards must be placed on the bottom of your library in a random order. Note that you do not reveal the cards you take unless an effect specifically says otherwise.

Resolving the Counter Mode

When choosing the second mode, you target a spell on the stack. The spell is countered unless its controller pays {2} multiplied by the value you chose for X. For example, if you cast this for X=3, the opponent must pay 6 mana to prevent their spell from being countered.

Common Strategic Mistakes

A common mistake is forgetting that X is chosen when the spell is cast. You cannot change the value of X or the selected mode once the spell is on the stack. Additionally, remember that if you cast this for X=0, the first mode allows you to look at zero cards, and the second mode asks the opponent to pay 0 mana, which they can always do.

Interaction examples

Securing the Win

Counterspell

If your opponent attempts to cast Counterspell to stop your finisher, you can respond with Thassa's Intervention. By choosing the second mode with X=2, your opponent must pay 4 mana. If they cannot, their Counterspell is removed from the stack, allowing your original spell to resolve.

Digging for Answers

An Offer You Can't Refuse

If you are facing a dangerous noncreature spell but don't have an answer in hand, you can cast Thassa's Intervention for X=5. You look at the top five cards of your library and find An Offer You Can't Refuse. You put that card into your hand and the rest on the bottom of your library. Now you have the specific counterspell needed for the next turn.