Rules Tip of the Day: The choice of whether or not to take advantage of a triggered ability that uses the word 'may' is not decided until the triggered ability resolves. If this triggered ability targets, you must choose a target if there is one available as the ability goes on the stack, even if you do not plan on choosing to have the ability take effect.

Q: I play Snakeform and target Chameleon Colossus, and in response, my opponent pumps Chameleon Colossus using his ability. Will the 1/1 green Snake still be a 1/1 green Snake after the pump resolves and Snakeform resolves, or will he be a 5/5 green Snake?

A: It will be a 1/1 green Snake. The increased power and toughness given by Chameleon Colossus's ability is calculated when the ability resolves and is locked in. In this example, the power of the Colossus is four when the ability resolves, so the Colossus will get +4/+4. However, the effect from Snakeform is applied in the same layer, and the timestamp from this effect will be later than the one from Chameleon Colossus's ability. This means when calculating its P/T you start with a 4/4 Chameleon Colossus, it becomes an 8/8, and then finally a 1/1.

Q: If I have an Avalanche Riders and a Cauldron of Souls in play at the beginning of my upkeep, can I put echo on the stack, give the Riders persist with the Cauldron, choose not to pay the echo and sacrifice the Riders, and then have the Riders return to play with a -1/-1 counter to destroy another land?

A: Yes, that works. Keep in mind that you will have to pay echo in the upkeep step of your next turn or sacrifice the Riders.

Q: Can Plated Slagwurm be named for Runed Halo?

A: Yes. Choosing a card name when Runed Halo comes into play does not target anything.

Q: I have Mana Reflection and Lotus Petal in play. When I tap and sacrifice the Lotus Petal, do I get two mana?

A: Yes. Lotus Petal's mana ability does have you tap it, so Mana Reflection's ability is applied. It does not matter that you also sacrifice the Petal.

Q: If I have a Horde of Notions in play and choose to use the Horde's activated ability to play a Cloudthresher from my graveyard, is the Cloudthresher counterable?

A: Yes. When Horde of Notions' ability resolves, you can play the targeted Elemental card. This card is played as a spell and it can be countered by effects that counter spells.

Q: I have a Pyromancer's Swath in play, and an Ignite Memories targeting my opponent. If my opponent reveals a land, does it do two damage or zero damage from the Ignite Memories, plus two damage from the Swath? Or does doing zero damage not exist?

A: No damage will be dealt. Pyromancer's Swath only increases the amount of damage that would be dealt if damage would actually be dealt. If a land card is chosen from yoru opponent's hand this means that zero damage is being dealt, so the effect from the Swath will not be applied.

Q: If I play Surge of Zeal on a legal target, like a red creature I control, and I play red creatures after it resolves in the same turn, do the other red creatures have haste, even if they were not there when I cast the spell?

A: No. The effect from Surge of Zeal only affects those creatures that shared a color with the targeted creature and were in play when Surge of Zeal resolved. Creatures that enter play after Surge of Zeal resolves will not be affected, even if they do share a color with the creature that was targeted.

Q: I have random enchantments in my graveyard along with Copy Enchantment, but no enchantments in play already, and I cast Replenish, will I be able to choose one of those enchantments to copy with Copy Enchantment?

A: No. All of these enchantments return to play at the same time. You choose an enchantment in play for Copy Enchantment to copy as it comes into play, which means before any of these enchantments are actually in play. If you cannot choose a copy, then Copy Enchantment will still enter play, but as itself, which for the most part does nothing.

Q: I was recently at a local Vintage tournament when a bizarre interaction came up. The interaction in question was between Word of Command and the opponent's Yawgmoth's Will. Player A had used Word to "steal" the Will, and was curious if he essentially gained access to control of his opponent's graveyard as a result.

A: No. He can make his opponent play his Yawgmoth's Will, but that just means that his opponent will be able to play cards from his graveyard that turn. The player that plays Word of Command does not gain control of a card they force an opponent to play. This spell is still controlled by its owner.

Q: If a creature blocking The Wretched dies, will that creature go to the player controlling The Wretched?

A: No, you only gain control of those creatures if they are still in play at the end of combat after blocking The Wretched. The Wretched's ability only affects creatures, it does not bring creature cards back into play.