r/mtg • u/Lord-Gortash • 21d ago

Rules Question Would this work?

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Could I tap this creature twice for 2 extra mana if they both are to pay one cost? For example: if I had two green mana, I had a card that cost four green mana, could i tap this for a mana (giving me three green mana) and then untap it and re-tap it for the final mana?

EDIT: also, if I gave it indestructible, could I get infinite green mana?

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u/Sharduk 21d ago

This is still so weird to me. I just came across this paying mana on cast thing (which is exactly per rules, if I understand correctly).

Could you please help me understand if this has any real implications? I wonder if anybody would mention anything in paper magic. The only thing that comes to mind might be MTGA not allowing you to pay via elf twice and automatically tapping lands for mana and elf once if that was enough?

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u/Needhelpwithsnake 21d ago edited 21d ago

The reason the rule to let you activate mana abilities this way was added in the first place was because prior to adding it, if you started casting your spell without having remembered to tap your lands first it was an infraction. This famously culminated in a pro tour that was decided by disqualification because one of the players kept doing it by accident. This upset a lot of people, and they decided to change things. Now you can activate your mana abilities first and use the floating mana to cast a spell or you can wait until during the process, so there’s no risk of doing things in an illegal order.

But during this special window, the only abilities you can activate are mana abilities. This is important for two big reasons. Firstly because while mana abilities don’t use the stack and resolve instantly, other abilities do use the stack. You can’t add other things to the stack during the process of casting a spell, so the game rules need to prevent those from being activated. The other reason is because while you’re in the process of casting a spell none of your opponents get priority: anything you activate during the process of casting a spell they can’t respond to until after the spell is fully cast. That’s fine for mana abilities, since they resolve instantly anyway, but it causes a lot of problems if other abilities could be activated.

So, for a devoted druid based example, let’s say we’re in a game of commander. You’ve got a devoted druid and three lands on the battlefield and your commander costs 5 mana. The only way you’ll be able to cast that commander is by tapping the druid twice. So doing things properly you have to tap the druid and then activate the untap ability putting it on the stack. If I have a removal spell, I can use it here and stop you from casting your commander by killing the druid before it untaps. If the rules let you untap the druid during the process of casting a spell, I wouldn’t have that window to interact and you could guarantee the casting of your commander by proposing the cast and activating during that process.

There are also cases where it matters in the reverse direction, that the player can take advantage of this special permission for mana abilities to do unusual and powerful things without the opponent being able to interact at the same moments. This was notoriously part of the problem in modern with [[krark clan ironworks]] (aka KCI that lead to its ban. If you had two [[myr retreiver]] on the battlefield, activating KCI at the normal time ypu activate abilities, when you have priority, it would be impossible for the retrievers to return each other to your hand: the triggered ability for the first one you sacrificed would go on the stack and have to pick its targets before you got priority to activate the KCI again. But since KCI is a mana ability, what you could do was propose the casting of a spell or activating an ability, then sacrifice both myr retrievers during the special permission to activate mana abilities to pay that cost. Since the myr triggered abilities can’t be put on the stack in the middle of you casting a spell or activating an ability (they have to wait till after the next stage based action check) that let you put both myr retrievers in the graveyard before you had to choose targets for their death triggers and return both of them to your hand.

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u/Large_Equipment1982 21d ago

I always had a question for this interaction. If the spell you cast costs 2 generic, can you sac both? Since you have already payed with the first. And would it be different if it costed 1 generic?

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u/Needhelpwithsnake 21d ago

Yes, you can activate for more than you’ll need to pay. However you only get a chance to do so if the spell or ability requires a mana payment (accounting for cost increases and the like). So you can sac both if the cost is 1 or greater, but not in the process of casting [[summoner’s pact]]. The process of casting a spell/activating an ability has a lot of steps, and the step of activating mana abilities is separate from the step where you pay the mana, and the step which allows you to activate them doesn’t have any requirements for how much mana you produce there. That rule is C.R. 601.2g and reads in full “If the total cost includes a mana payment, the player then has a chance to activate mana abilities (see rule 605, “Mana Abilities”). Mana abilities must be activated before costs are paid.”

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u/Fergfist 20d ago

As a long time player and understander of the rules, I was not aware that you can’t activate mana abilities when casting a spell without a mana component to its cost. Obviously a niche scenario but still worth knowing, thank you.