Last week we covered the basics of casting spells. This week, let's look at the various applications of these rules. Obviously, something like "I'll tap my Mountain and cast Lightning Bolt" doesn't need much fanfare. But today we'll dig into some of the more interesting things we can do. I sorted these sections from roughly "most common to come up" to "likely only to come up in hypotheticals."

As a reminder, you can refer to CR 601 for the nitty-gritty of the rules involved in these cases.

im in ur spell sacrificin ur d00dz

Since we total up costs before making payments, sacrificing a cost-reducing creature works in our favor. For instance, if I control Baral, Chief of Compliance, I can sacrifice him to cast Fling or Heartfire and they would still only cost {R}. Baral's cost reduction applies in step 6 and gets locked in before we actually make payments in step 8.

Things That Once Were

Many a Modern player will remember the dark days of the Krark-Clan Ironworks (KCI) combo deck. This deck functioned by abusing step 7 of casting a spell, activating mana abilities. When the pilot proposed a spell that required a mana payment, they could sacrifice multiple artifacts to KCI in the middle of casting the spell. Then, since those artifacts had several triggers that wanted to go on the stack at the same time, those artifacts' triggers could target one another.

While the Magic Tournament Rules generally aim to reward better rules knowledge, this one was a bit beyond the pale. KCI broke a lot of conventions of how Magic "should" be played, and also ran into some durdly turns, so it got the ax.

Abusing Treasure For Fun And Profit

We've seen a lot of cards that produce Treasure tokens lately. Since their only ability is a mana ability, we can do some tricky things with them and cards that cost less for artifacts we control.

Let's look at Reality Heist. I can cast this card if the only sources of mana I have are four Treasure tokens. In step 6, determining the spell's cost, I still control four Treasures, so Reality Heist's total cost becomes
{5}{U}{U} - {4} = {1}{U}{U}

Then I can activate the Treasures' mana abilities in step 7, and pay for the spell in step 8. Remember, once we've determined a spell's cost in step 6, that cost is locked in. Anything that happens later in the spellcasting process won't affect it. So in the end, we can cast this 7-mana spell with only four artifacts. Not too shabby!

This works identically for spells like Thoughtcast, as well. After all, affinity is just "this spell costs {1} less to cast for each artifact you control" but shorter.

K'rrik is K'racked

K'rrik, Son of Yawgmoth is an odd duck, mostly because of his second ability. While his ability to let you pay 2 life instead of {B} might look an awful lot like Phyrexian mana, it actually works slightly differently.

See, if I want to cast Dismember or some other spell with Phyrexian mana, I usually make that call in step 2, when I have to make most choices for the spell (mode, alternate cost, so on). However, if I want to use K'rrik's payment modification, that doesn't apply until step 8, actually paying the costs.

So, practically, what does this mean? This slight difference doesn't particularly matter unless we get our old friend Trinisphere involved.

For the following situations, let's say I'm playing K'rrik in commander, and my opponent controls Trinisphere.

Scenario A: I cast Dismember and say, "I'll pay the 2 life for each Phyrexian mana" in step 2. When I get to step 6, Trinisphere says "Hey, hold on, that costs {1} and 4 life. You have to pay {3} and 4 life."

Scenario B: I cast Dismember and say, "I'll pay the {B} for each Phyrexian mana" in step 2. When I get to step 6, Trinisphere has no complaints. As far as it can tell, I'm going to pay {1}{B}{B} for this spell. But it turns out that I lied to poor old Trinisphere. In step 8 I'm going to pay 2 life for each {B} thanks to K'rrik.

Weird, right?

Hic Sunt Dracones

Remember last week when I said this in step 5, the last legality check?

If it turns out that a spell's proposal is illegal, the game rewinds to just before the announcement started. Any mana abilities are undone, and the spell goes back to the zone it was in before.

Me, last week, in simpler times

It turns out I fibbed a little bit. Some mana abilities can't be undone. Let's poke around farther down in the Magic Comprehensive Rules to check it out. I emphasized the relevant part.

726.1. If a player takes an illegal action or starts to take an action but can’t legally complete it, the entire action is reversed and any payments already made are canceled. No abilities trigger and no effects apply as a result of an undone action. If the action was casting a spell, the spell returns to the zone it came from.

Each player may also reverse any legal mana abilities that player activated while making the illegal play, unless mana from those abilities or from any triggered mana abilities they caused to trigger was spent on another mana ability that wasn’t reversed. Players may not reverse actions that moved cards to a library, moved cards from a library to any zone other than the stack, caused a library to be shuffled, or caused cards from a library to be revealed.

Magic Comprehensive Rules

Sometimes we can fail to cast spells because of random elements in the process. While step 5 is the last "hard" legality check in casting a spell, the cast can still be illegal if we can't comply with one of the other steps for some reason.

Let's say I'm casting Grizzly Bears, and the only permanent I control is Selvala, Explorer Returned. If I activate Selvala and everybody reveals a land, the ability won't make any {G} for me to use. But wait! Since Selvala's mana ability has each player draw a card, this is a mana ability that can't be reversed. The spell cast is reversed as much as it can be, which in this case just means that the Bears end up back in my hand.

Cleanup

That's a wrap on this week, folks. Hopefully, you can use some of these nifty tricks in upcoming games. Do note that if someone tries to do anything cute with Selvala, take a page out of Hank Hill's playbook. Ask them politely but firmly to leave.

Question of the week: What's the cleverest thing you've ever done casting a spell? (I know, I know, the same question as last week - but they're partner articles!)