Rules Tip of the Day: The very first part of announcing a spell or ability is to put it on the stack. This means that you immediately put the card on the stack when you play a spell.

Q: I was curious about the interaction between Viscerid Drone and Balduvian Frostwalker. If I turn a Snow-Covered Swamp into a creature, would sacrificing it to the drone satisfy both conditions?

A: No, you can sacrifice this animated Snow-Covered Swamp as the creature or the Snow land, but not both. In order to complete the payment you will have to sacrifice some other creature or Snow land.

Q: When you discard a card to put two counters on Lightning Storm, can your opponent respond by discarding a card, putting four total counters on the stack, making one of the new targets take seven damage, while the first takes five?

A: You seem to misunderstand how Lightning Storm works. Lightning Storm only has one target. Lightning Storm's activated ability does not make copies of itself, it puts counters on the Lightning Storm on the stack and allows the player that last put counters on it to change the target of the Lightning Storm. If the land card discarded by your opponent is the last card discarded, then this Lighting Storm will deal 7 points of damage to the target he chose. Previous targets of the Lightning Storm will not receive damage.

Q: If I control two Adarkar Valkyries, is it legal to tap them, targeting each other, to save them from a Wrath of God?

A: Yes. When a card refers to itself by name, it means this object only. You can use the ability of one Adarkar Valkyrie to target another in play.

Q: I have Braid of Fire in play with four age counters. I also have Magmatic Core in play with four age counters. I untap, put Magmatic Core's Cumulative Upkeep trigger on the stack, then put Braid of Fire's CU trigger on the stack. We both pass priority. I resolve Braid of Fire's CU, choose to pay, and add 5 mana to my pool. Then I must pass priority again and you play Mystic Melting on Magmatic Core. What happens now? Can I still resolve the upkeep trigger of Magmatic Core? If yes, do I pay four or five?

A: Yes, you can choose to pay the Cumulative Upkeep cost of this permanent that has just left play. However, you'll only be able to pay four mana, as that is how many age counters were on Magmatic Core when it left play. So you'll have to find a way to spend this last red mana, or else take a point of mana burn when the phase ends.

Q: If a player has two Void Maws in play, do they get to pick which one removes a creature card going to the graveyard from the game?

A: The controller of the creature when it leaves play gets to choose which Void Maw will remove it from the game. The replacement effect generated by each Void Maw will try to remove a single creature card from the game. Whenever one or more replacement effects could be applied to a single event, the controller of the affected permanent gets to choose which to apply first. Then the other is applied if it still applies. In this example, the ability of the first Void Maw to be applied will remove the card from the game and the other won't do anything.

Q: Can I tap the Verdant Eidolon to pay for one green mana of Siege Wurm, and then sacrifice it to add three more green mana to my pool?

A: No, that does not work. You can either use the Eidolon's mana ability to generate mana to pay for this spell or you can tap the Eidolon to lower the cost, but not both. This is because when announcing a spell, you tap creature for convoke after you have generated all the necessary mana to pay for the spell. If the Edilon is not in play at this point, you can't tap it to lower the cost.

Q: Would a Leave No Trace destroy all other enchantments on the field if Privileged Position was the target, or would Privileged Postion's effect still protect the enchantments?

A: Leave No Trace only targets one enchantment; the Radiance effect does not target anything. When this Leaves No Trace resolves, it will destroy the targeted Privileged Position and all other green and white enchantments, including those controlled by the controller of the Privileged Position.

Q: My friend has Circu, Dimir Lobotomist in play, and he plays a blue spell. I have Eight-and-a-Half-Tails in play. Can I change the color of the spell, so Circu's ability don't work?

A: No. By the time you can change the color of the blue or black spell that your opponent has played, Circu's ability will have triggered and already gone on the stack. Changing the color of this spell at this point will not retroactively prevent Circu's ability from triggering.