How do I cast spells?
Asked by Thetreymeister 8 months ago
Example 1: I have 4 artifacts in play, one being a Lotus Petal, and no other available mana. I want to cast Thoughtcast. Can I announce the casting of Thoughtcast, locking in the cost of a single blue mana due to affinity, then sacrifice the Lotus Petal for the blue mana needed?
Example 2: I have a Lion's Eye Diamond and no other available mana. Can I announce the casting of Yawgmoth's Will and then pay the three mana by sacrificing LED to it's ability?
Thanks
The answer to 2 is no. As originally printed, Lion's Eye Diamond says "play this ability as a mana source," which would allow you to move your spell to the stack, then activate it to pay for the spell. When it was printed you had to float your mana before announcing the spell, so it wouldn't have let you pay for a spell cast from your hand. To maintain the original functionality, Lion's Eye Diamond now says "activate only as an instant," which means you can only activate it when you have priority, not during the casting of a spell.
(10/4/2004) The ability is a mana ability, so it is activated and resolves as a mana ability, but it can only be activated at times when you can cast an instant. Yes, this is a bit weird.
December 29, 2025 2:57 p.m.
Rhadamanthus says... #3
FYI I have re-selected the "Accepted answer" based on the correction to the Lion's Eye Diamond question.
Polaris says... #1
1: Yes. Per rules 601.2 f, g, and h, you determine the cost to cast the spell, then activate any mana abilities you need to pay the costs, then pay the cost from 601.2f to cast the spell. You can wait to sacrifice Lotus Petal until after the cost for Thoughtcast is locked in at .
2: Yes. Moving the card to the stack is the first step in proposing to cast a spell (rule 602.1a). If the casting is determined to be invalid this will be taken back, but a spell has already left your hand by the time you discard cards or similar to pay the cost to cast it. You do not discard your Yawgmoth's Bargain to Lion's Eye DiamondGC when using the Diamond to pay the casting cost.
December 26, 2025 11:46 p.m.