When an ability obliges a player to sacrifice a creature, then he must sacrifice any creature if he has one in play. Logically that means that the only way to bypass this is by having no creatures in play. Right?
Example
I cast Fleshbag Marauder. My friend has 2 creatures in play and 1 of his creatures has an ability to sacrifice itself, as in Vampire Hexmage. He choses to sacrifice Vampire Hexmage for the Fleshbag Marauder's effect, then he decides to sacrifice Vampire Hexmage for it's own sacrifice ability at instant speed in order to trigger its effect. He of course can do that but according to me he then still has to choose another creature to sacrifice for Fleshbag Marauder's effect, because he has to sacrifice A creature. The only way for him to bypass it would be if he could sacrifice both, for example with Viscera Seer 's ability because he wouldn't have any creatures left to sacrifice for Fleshbag Marauder's ability. Right?
A friend of mine says that it's incorrect of me to sacrifice Shriekmaw "twice". I cast Shriekmaw for its evoke cost so it enters the battlefield and before it gets sacrificed by its evoke effect I sacrifice it with Carrion Feeder 's ability. He says it's exactly the same as he wants to do with Fleshbag Marauder's effect and Viscera Seer's ability. I beg to differ because there's a clear difference between Fleshbag Marauder's effect "sacrifice A creature" and Shriekmaw's evoke effect "IT's sacrificed". If Shriekmaw isn't on the battlefield any more it can't be sacrificed anymore, but it doesn't force me to sacrifice any other creature as Marauder's effect does.
Correct?
You seem to understand the situations pretty well and your conclusions appear to be correct. Marauder says to sac "a" creature and sacrificing that creature happens on resolution of Marauder's ability. There is no point where they choose what to sacrifice but then get to take another action before actually sacrificing it. As far as the Marauder is concerned, Hexmage doesn't even exist when they go to sacrificing something for the trigger.
And yes, Evoke works the way you want it to as well. Evoke is making you sacrifice that creature and you are free to sacrifice it before its own trigger resolves. Then, when it does, it sees the creature isn't around anymore so you clearly can't sac it and the game moves on.
So, yes, there is a pretty clear, and significant, difference between those two situations and it looks like you came to the right conclusion on both.
You more or less got it. Only a few minor corrections.
With the fleshbag and Hexmage. If your opponent chooses to sacrifice the Hexmage to the Fleshbag's effects they can't then choose to use the Hexmage's ability to sacrifice itself. This is because there is no time between choosing what to sacrifice for fleshbag and it happening. This is because it doesn't target it simply instructs the player to do something. To see a difference look at Mercy Killing. If you target the hexmage with mercy killing; they can sacrifice the hexmage to its own effect and then not sacrifice anything to mercy killing.
As for sacrificing a creature "twice". It just doesn't happen as you said. There is an ability on the stack saying to sacrifice a specific creature. However, if that creature isn't on the battlefield you can't sacrifice it. If there are any complications because you couldn't sacrifice it then those occur or don't occur but evoke just have you sacrifice the creature.
With the fleshbag and Hexmage. If your opponent chooses to sacrifice the Hexmage to the Fleshbag's effects they can't then choose to use the Hexmage's ability to sacrifice itself. This is because there is no time between choosing what to sacrifice for fleshbag and it happening. This is because it doesn't target it simply instructs the player to do something. To see a difference look at Mercy Killing. If you target the hexmage with mercy killing; they can sacrifice the hexmage to its own effect and then not sacrifice anything to mercy killing.
So what you mean is that it's only possible to sacrifice a creature before it's sacrificed if it's targeted because then there's time between targetting and sacrificing/destroying/exiling it?
So a creature getting targeted as mentioned above, getting sacrificed automatically due to evoke effect, same goes for echo effect.
Are there any other exceptions that make it possible to sacrifice a creature before it gets sacrificed/destroyed/exiled?
I'm especially thinking of the combat phase, ie before or after declaring attacking and blocking.
A friend of mine used to sacrifice a creature after blocking with it which destroyed it and then after losing the battle sacrificed the same creature before it went to the graveyard. That seems illogical to me because once it's destroyed by combat there isn't time between it getting destroyed and entering the graveyard... Right?
You can sacrifice a creature (if the nessessary means for that are provided) in response to any object on the stack, that would cause you to sacrifice it as part of its effect, targeted or not. If the object is targeting, then the sacrifice for the effect is locked in at the time the object is put on the stack. Whereas if it is not targeting, the effect will determine what if anything will be sacrificed for its effect when it resolves. If no creature can satisfy the criteria, then no creature gets sacrificed. This is, for example, the case with evoke. The evoke trigger demands you sacrifice that specific creature, but there is no targeting. If the creature doesn't exist anymore, evoke cannot make you sacrifice it and the game moves on.
There is no window of priority for a player to activate an ability or cast a spell in between combat damage being dealt and lethally damaged creatures dying. While there is a delay, players are not given the chance to act.
Example
I cast Fleshbag Marauder. My friend has 2 creatures in play and 1 of his creatures has an ability to sacrifice itself, as in Vampire Hexmage. He choses to sacrifice Vampire Hexmage for the Fleshbag Marauder's effect, then he decides to sacrifice Vampire Hexmage for it's own sacrifice ability at instant speed in order to trigger its effect. He of course can do that but according to me he then still has to choose another creature to sacrifice for Fleshbag Marauder's effect, because he has to sacrifice A creature. The only way for him to bypass it would be if he could sacrifice both, for example with Viscera Seer 's ability because he wouldn't have any creatures left to sacrifice for Fleshbag Marauder's ability. Right?
A friend of mine says that it's incorrect of me to sacrifice Shriekmaw "twice". I cast Shriekmaw for its evoke cost so it enters the battlefield and before it gets sacrificed by its evoke effect I sacrifice it with Carrion Feeder 's ability. He says it's exactly the same as he wants to do with Fleshbag Marauder's effect and Viscera Seer's ability. I beg to differ because there's a clear difference between Fleshbag Marauder's effect "sacrifice A creature" and Shriekmaw's evoke effect "IT's sacrificed". If Shriekmaw isn't on the battlefield any more it can't be sacrificed anymore, but it doesn't force me to sacrifice any other creature as Marauder's effect does.
Correct?
And yes, Evoke works the way you want it to as well. Evoke is making you sacrifice that creature and you are free to sacrifice it before its own trigger resolves. Then, when it does, it sees the creature isn't around anymore so you clearly can't sac it and the game moves on.
So, yes, there is a pretty clear, and significant, difference between those two situations and it looks like you came to the right conclusion on both.
With the fleshbag and Hexmage. If your opponent chooses to sacrifice the Hexmage to the Fleshbag's effects they can't then choose to use the Hexmage's ability to sacrifice itself. This is because there is no time between choosing what to sacrifice for fleshbag and it happening. This is because it doesn't target it simply instructs the player to do something. To see a difference look at Mercy Killing. If you target the hexmage with mercy killing; they can sacrifice the hexmage to its own effect and then not sacrifice anything to mercy killing.
As for sacrificing a creature "twice". It just doesn't happen as you said. There is an ability on the stack saying to sacrifice a specific creature. However, if that creature isn't on the battlefield you can't sacrifice it. If there are any complications because you couldn't sacrifice it then those occur or don't occur but evoke just have you sacrifice the creature.
So a creature getting targeted as mentioned above, getting sacrificed automatically due to evoke effect, same goes for echo effect.
Are there any other exceptions that make it possible to sacrifice a creature before it gets sacrificed/destroyed/exiled?
I'm especially thinking of the combat phase, ie before or after declaring attacking and blocking.
A friend of mine used to sacrifice a creature after blocking with it which destroyed it and then after losing the battle sacrificed the same creature before it went to the graveyard. That seems illogical to me because once it's destroyed by combat there isn't time between it getting destroyed and entering the graveyard... Right?
There is no window of priority for a player to activate an ability or cast a spell in between combat damage being dealt and lethally damaged creatures dying. While there is a delay, players are not given the chance to act.
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