Rules Tip of the Day: Some objects—like lands, face-down cards, and a few other cards, do not have a mana cost. However, even cards without a mana cost have a converted mana cost. As the mana cost is undefined, the CMC is zero.

Q: Player A attacks with Knight of Dusk. Player B blocks with a Grizzly Bears. Player A activates the Knight's ability. Player B plays Boomerang on the Knight of Dusk. Will the Bears still be destroyed?

A: No. When Knight of Dusk's ability resolves, the targeted creature is still a blocking creature, but it is not blocking Knight of Dusk any longer, so it is not a legal target. Because of this, Knight of Dusk's ability will be countered on resolution, and nothing will happen.

Q: When Chronomantic Escape resolves, can I use effects such as Meditate or Eater of Days to extend the use of Chronomantic Escape?

A: Yes. If your turn is skipped for some reason, then the effect from Chronomantic Escape will last until you do actually take a turn.

Q: My opponent has a Daru Spiritualist in play, and I have a Serendib Sorcerer and a Merfolk Thaumaturgist. I target the Spiritualist with the Sorcerer's ability first, then with the Thaumaturgist's ability. How does this resolve?

A: Regardless of the order that these two abilities are played and resolve, the Spiritualist will end up as a creature with zero toughness and will go to the graveyard. This is because effects like Merfolk Thaumaturgist's ability that causes a creature's power and toughness to switch are always applied last when calculating the creature's power and toughness. This is true even if the switch effect resolved before other effects that are applied to this creature's power and toughness. In this example, the last effect to resolve will be the power- and toughness-setting effect of the Serendib Sorcerer. This effect will end up negating the effect from the Spiritualist's triggered ability. In the end, the Spiritualist will end up as a 2/0 creature, and will go to its owner's graveyard.

Q: My opponent has Magus of the Abyss and a Lord of the Pit in play. At the beginning of his upkeep, is he able to sacrifice and destroy the same creature?

A: Sort of—his creature will end up being sacrificed, not destroyed, but he'll only lose one creature. As he controls both the Lord of the Pit and the Magus of the Abyss, he can choose the order that these two abilities go on the stack. He can put the Magus' ability on the stack first and choose to target creature X at this point, followed by putting the Lord of the Pit's ability on top of the stack. Then, when the Lord's ability resolves, he can choose to sacrifice the creature that was targeted by Magus' ability. This will cause the Magus' ability to become countered on resolution when it attempts to resolve. This 'trick' works because you choose the targets of targeted spells and abilities when they go on the stack. But the Lord of the Pit's ability does not target anything, and you choose what creature to sacrifice when that ability resolves.

Q: I have Wild Pair and Akroma, Angel of Wrath in play, and I play another Akroma, Angel of Wrath. Will they both be sacrificed from the legends rule with the Wild Pair triggered ability still on the stack, so that when the trigger resolves, I can search my library for another Akroma, Angel of Wrath and have it survive?

A: Yes, that works as you describe. It works because the 'legend rule' is a state-based effect that will be checked immediately after the second Akroma enters play. So even before the Wild Pair triggered ability can go on the stack, both of these first two Akromas will go to the graveyard. Then, when Wild Pair's ability resolves, it will use last-known information about the creature that triggered its ability and you will be able to search for a creature with a combined power and toughness of 12. The only question that remains is why you would want to do this.

Q: I have No Mercy in play and my opponent attacks me. I play Darkness. Does his creatures die, and do I receive no damage?

A: No. If the combat damage is prevented then No Mercy's ability will not trigger. So this attacking creature will not be destroyed.

Q: I have a Grizzly Bears I've taken with Control Magic. My opponent casts Lightning Bolt targeting the Bear; can I Boomerang Control Magic and have the Bolt still resolve? If lethal damage to the Bear is on the stack during combat, and I Boomerang the Control Magic, does the Bear still die?

A: In both situations, the Bear will end up receiving lethal damage and go to the graveyard. In the first situation, causing this creature to revert to being under the control of its owner will not change the fact that it is targeted by this Lightning Bolt. It is still the same creature, and it will be dealt three points of damage. And combat damage on the stack will be dealt as assigned, even if the creature that had the damage assigned to it changes controllers or is removed from combat. So in the second situation the Bear will die due to lethal combat damage.

Q: I see a lot of people use the following combo to draw cards, and I was wondering if it works. They have Argothian Enchantress in play. They play Rancor and draw a card, but since the Enchantress can't be targeted, the Rancor fizzles and goes to the graveyard, then back to their hands. They repeat the process. Can you play Rancor, targeting something that can't be targeted?

A: This does not work for a few reasons. As the Argothian Enchantress cannot be targeted, a player cannot even announce Rancor and target the Enchantress. If, for some reason, the Enchantress was targetable, and later became untargetable after Rancor was legally played but before it resolved, then the Rancor spell would go to the graveyard from the stack. This means that it would not have been in play, and its leaves-play triggered ability would not trigger.