If I have four open mana, one of which is {B} to cast Undercity Informer with one mana remaining, if I go to sacrifice it, can the opponent respond with a kill spell to stop me sacrificing it? In this case is it better to wait till I have two mana open after casting it?


3 Answers 3


Normally, your opponent will not be able to stop you with a kill spell.

When a spell resolves; the active player gets priority:

116.3b The active player receives priority after a spell or ability (other than a mana ability) resolves.

Normally if you are casting a creature spell, that means you are the active player; as you can normally only cast creature spells on your turn. Because you have priority, you can activate Undercity Informer’s ability; before your opponent had any chance to act. You pay the costs when you activate the ability, which includes sacrificing a creature. Whether you sacrifice Undercity Informer or a different creature; the ability is activated and on the stack. Only then does your opponent get priority.

Also, even if you do not choose to activate the ability the first chance you get; if your opponent casts a kill spell, then you can respond to that by activating the ability at that point.


As a general rule, players cannot stop a cost from being paid in Magic the Gathering. This is for a few reasons, but the most important is players can only act when they have priority. Activated abilities in Magic are written "Cost: Effect" so everything that is before the colon has to be done while putting the ability on the stack, none of that can be interrupted as it is a cost.

For this the most common way in your situation would play out like this, with you as active player:

  1. Cast Undercity Informer paying {2}{B}. Informer is put on the stack.
  2. All players pass priority, Informer resolves and priority returns to Active Player (you)
  3. Activate informer's ability, by paying {1} and sacrificing the Informer. Ability goes on stack.
  4. You pass priority - this is the first time your opponent has priority after Informer resolved and the Informer is already in the graveyard.

While things can be done in between these steps, this is what you described. By the time your opponent has the opportunity to do anything, your Informer is already in the graveyard - because sacrificing was a cost of the ability, not part of the effect.

Now lets see what would have happened if you hadn't used Informer immediately, or had cast it with flash on an opponent's turn - if someone had a chance to act before you activated the ability.

  1. Opponent uses a spell or ability that will destroy or exile Informer. They pass priority to you.
  2. You activate informer's ability, by paying {1} and sacrificing the Informer. Ability goes on stack.
  3. Everyone passes priority, Informer's ability resolves.
  4. Opponent's spell or ability is removed from the stack doing nothing as it no longer has any legal targets.

There are ways in this second scenario that they can prevent you from using your informer before it is destroyed, if you can't cast spells or abilities because they use a spell with split second like Sudden Shock or Sudden Death to kill your Informer, you can't do step 4 above until their spell is off the stack, at which point your informer is dead. There are also cards that prevent people from sacrificing to pay costs, like Angel of Jubilation, which will prevent you from using Informer's ability at all.


It is difficult stop you from casting and sacrificing the Informer by destroying it.

No matter what spell or ability they play, or how they time it: before their destruction resolves, you have an opportunity to cast instants and flash spells, as well as activating abilities. Even more importantly, if it is your turn, after the Informant spell resolves and is put onto the battlefield, you are the first player who gets to pay anything.

Summa summarum, it is quite difficult to stop you.

Countering the Informant spell is possibly the most available method.

One way to stop it even if it enters the battlefield is Sudden Death, which will stop you from activating the Informant if it is your opponent's turn, and the first thing they do after the Informant enter the battlefield is to kill it. Which means you must have managed to play the Informant on your opponent's turn in the first place. There are also cards that limit players' abilities to activate the ability in the first place, like Angel of Jubilation.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .