am I allowed to cast grave exchange if I have no cards in my graveyard just to have other player sacrifice a creature?
am I allowed to cast grave exchange if I have no cards in my graveyard just to have other player sacrifice a creature?
No. You need to be able to pick a valid target in your graveyard to cast the spell.
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how about the other way if other player has no creatures and I just wanna return a card from my graveyard?
Yes, you can do that.
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how come one you can do it one way but not the other way and also didnt u say that to cast a spell you need to be able to choose all the targets
The only thing the second part of Grave Exchange targets is "target player". It doesn't matter whether or not they control any creatures.
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how can the target be legal if he controls no creatures?
Because it doesn't say they have to control a creature.
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it does it says "Target player sacrifices a creature" just like the first part says you need to return card from your graveyard
Sacrificing a creature is just what it makes the player do, it's not a targeting restriction.
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what if in response to me casting the grave exchange, the other player somehow gets rid of his creature i targeted? do I still get a card from the graveyard?
...I just said, you don't target any creatures. You target only the player (and the creature card in your graveyard). When Grave Exchange resolves, they chooes a creature they control at that point and sacrifice it.
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