Judge Alex, Rules Attorney at Law — That Interaction Does What?!

Judge Alex banner image
(Rules Lawyer | Art by Dmitry Burmak)

Wait, That's Illegal

(Flavor Judge | Art by Mike Burns)

Hello, I'm Alex, and I'm a judge who loves EDH. Our beloved format was created by judges, and I'm more than happy to uphold that legacy (if only by playing). There may not be a judge available for your casual EDH game, yet the eye-watering number of cards legal in our format creates an incomprehensible number of possible interactions between them. I am sure you've heard by now that top scientists have declared Magic the most complex game in existence, and it can certainly feel that way when you are staring down a Humility and Opalescence. Or Ashaya and Blood Moon. Or anything that has Banding.

The interactions we're looking at today are not necessarily the most complex, but rather those with the most strange and unintuitive results. With these interactions, you are sure to amaze your friends and melt their brains at your next game! By the time you're through reading this article, I can only hope you have called BS and asked another judge if that's really how that works.

Go Forth and Subtract Negative Numbers

(Nethroi, Apex of Death | Art by Slawomir Maniak)

Ah, Mutate. Is there any keyword in recent memory that causes as many unintuitive and confusing interactions? However, while our first example may have Mutate and the interaction involves mutating, we don't actually care all that much about the mutation itself. We're more into what that mutation triggers. Nethroi, Apex of Death is a curious Cat (slash Nightmare Beast) that wouldn't look out of place in a monster movie and has a monstrous text box to match.

When we pay Nethroi's exorbitant Mutate cost of {4}{G/W}{B}{B}, we would expect to get a massive effect in return, and it could be argued that we do. Whenever Nethroi Mutates, we can return any number of target creatures with total power 10 or less from our graveyard to the battlefield under our control. So we could get ten 1/1 creatures, or five 2/2s, or a single 10/10... you get the idea. Let's keep that grade school arithmetic in mind while we look at the other half of this interaction.

Scourge of the Skyclaves looks and feels like a sibling of Death's Shadow, a well-known one-drop in competitive formats. But while Death's Shadow's behemoth of a 13/13 body would be too much even for Nethroi, what do we make of Scourge's power and toughness? */* (often read star/star) looks like some sort of office shorthand, but here represents one of judges' many treasured initialisms.

A characteristic-defining ability, or CDA, is an ability that tells us information about an object that would normally be told to us in other places. For example, Transguild Courier might look quite fancy with a colorful beach ball of a five-color color indicator, but Wizards of the Coast opted to go with a CDA instead: "Transguild Courier is all colors." The reminder text "even if this card isn't in play" is quite pertinent here, reminding us that characteristic-defining abilities function in all zones, including in the hand, library, or in this case, graveyard.

So what do we make of Scourge's CDA? The */* points us toward its third ability: "Scourge of the Skyclaves's power and toughness are each equal to 20 minus the highest life total among players." That confusingly worded sentence holds true everywhere that Scourge exists, not just on the battlefield. Now, finally, we get to the strange yet tantalizing interaction itself!

Let's say we're in for a bit of a slow game of Commander, the kind with durdling, battlecruisers, and stalemates on the combat side. Sounds like a fun time! In our hypothetical scenario, each player's life total is still at 40, unchanged from their starting life total. What is Scourge of the Skyclaves's power and toughness now? Well, that should be easy, it's 20 - 40 = -20. If it were on the battlefield right now, it would be very dead. So let's say it's in the graveyard, where its power and toughness remain at an absurd -20/-20.

Now let's bring Nethroi back into the fray. When Nethroi Mutates (at great expense), we can reanimate 10 power out of the graveyard. But how does that interact with Scourge's unusual power of negative 20? Unbelievably, this interaction works out better than we could have ever hoped, and it's right back to the grade school math: 10 - (-20) = 30. So now that we've selected Scourge as one of the creatures Nethroi will reanimate, our budget skyrockets from 10 power to 30 power!

That's right, as long as one of our creatures is Scourge, we can then choose 30 power worth of creatures to reanimate with Nethroi instead of 10! Will you get an Impervious Greatwurm and Emrakul, the Promised End? Or perhaps thirty 1/1 creatures that somehow ended up in your graveyard? The sky(clave) is the limit, so pack that 'yard full of bodies for your new best friend Nethroi and its strange and confusing appearance and ability. In a bit of serendipity that beggars belief, at the time of writing, Scourge of the Skyclaves is included in 20% of Nethroi decks. With an interaction this nifty, shouldn't it be closer to 100%?

Selvala, Explorer of the Illegal World of Failure

(Selvala, Explorer Returned | Art by Tyler Jacobson)

Look who got a reprint in Streets of New Capenna! Selvala, Explorer Returned holds a dear place in my heart. With her Parley ability, she nets her controller green mana and life gain while giving the entire table a free draw! What's not to love? Even if you're not a steadfast group hug enthusiast like me, at least she's not as powerful as her mono-green counterpart, right? ...Right!? Well, you may have already heard Selvala's name uttered in the same sentence as Panglacial Wurm, a card infamous only in relation to her, but Selvala's exploration of the rules does not start and end with nearly unplayable Wurms erroneously embedded in your library. The true problem? She's too fast! But let's not get ahead of ourselves.

To understand Selvala's strange nature, we must first understand the process of casting a spell. From my experience, most Magic players tend to float their mana before revealing the spell they are about to cast. Somehow, it just feels right. However, "before you begin casting a spell" is most certainly not the only time Magic players can activate mana abilities, and it's not how the rules are written.

601.2a To propose the casting of a spell, a player first moves that card (or that copy of a card) from where it is to the stack. It becomes the topmost object on the stack. It has all the characteristics of the card (or the copy of a card) associated with it, and that player becomes its controller. The spell remains on the stack until it resolves, it’s countered, or a rule or effect moves it elsewhere.

So the first step of casting a spell is moving that card to the stack. Then things like modes and targets are chosen, then the total cost of the spell is calculated. Then, finally, the caster may activate mana abilities to pay the mana cost of the spell.

601.2g 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.

Alright, so what's a mana ability? Just an ability that adds mana, no? Let's continue our Magic Comprehensive Rules journey into the definition of exactly what a mana ability is.

605.1a An activated ability is a mana ability if it meets all of the following criteria: it doesn’t require a target (see rule 115.6), it could add mana to a player’s mana pool when it resolves, and it’s not a loyalty ability. (See rule 606, “Loyalty Abilities.”)

Let's compare Selvala's Parley ability with the criteria for a mana ability to see if everything checks out. It doesn't target, so we're good there. It's not a loyalty ability, and she's not even a planeswalker, so no problems there. Finally, the "adding mana" part... ah, so a mana ability doesn't actually have to net a player any mana. It's enough that the ability could do so, but it doesn't necessarily have to. Unlike most mana abilities, Selvala's Parley ability adds a non-deterministic amount of mana between 0 and N, where N is the number of players in the game.

So what's all this fuss with making sure Sevala's Parley ability is technically a mana ability? It's all in the timing. Earlier I mentioned how Magic players seem to have a habit of activating mana abilities prior to casting a spell, but crucially, mana abilities specifically are allowed to be activated during the spell-casting process, not solely before. For example, Chandra, Bold Pyromancer's +1 loyalty ability does add mana, but we can only float that mana prior to casting a spell, not during the casting itself, as it is not a mana ability.

Now that we have all the pieces, let's zoom out. Say we have three green mana available, Selvala is untapped, and there are 4 players in our pod. We crack a fetch land and begin searching our library, during which time we spy Panglacial Wurm, which costs {5}{G}{G}, and decide we want to cast it. Incidentally, we can see every card in our library while searching it, but we can't reorder any of them. We'll get back to that.

We begin casting Panglacial Wurm by moving it from our library to the stack, then we get to the part where we activate mana abilities to pay for the spell, so we activate Selvala's Parley ability. Each player reveals the top card of their library, and we see two lands and two nonland cards. We gain two life and add two green mana, then each player draws a card. That's {G}{G}, not enough to cast Panglacial Wurm, and we have no other mana sources available. What happens in this situation? Unfortunately, we've taken an illegal action and our opponents have already called a judge.

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.

Well, hey, it's okay. We'll just put Panglacial Wurm back in the exact spot in our library we pulled it from. You didn't reorder your cards while searching, did you? Then the rules say we just rewind the mana ability we activated and it's no harm, no foul. But wait, two things happened that we can't undo: each player revealed the top card of their library, then each player drew a card. If I could turn back time, if I could find a way to do it, I would, but I can't. Selvala's ability can't be undone because parts of it can't be undone. This isn't just illegal, this is... advanced illegal. While most EDH games are played unsanctioned (read: casually, outside of a tournament setting), tournament rules can still be referenced for relevant issues such as this. Let's check the Infraction Procedure Guide (IPG).

IPG 4.8. A person breaks a rule defined by the tournament documents, lies to a Tournament Official, or notices an offense committed in their (or a teammate’s) match and does not call attention to it. Additionally, the offense must meet the following criteria for it to be considered Cheating:

  • The player must be attempting to gain advantage from their action.
  • The player must be aware that they are doing something illegal.

"Cheating," goodness that's a dirty word! We've followed all the rules text on the card and the Magic Comprehensive Rules, how could that be cheating? Consider that while we were searching our library, we happened to see the top card. What if the information about that top card influenced our decision as to whether or not we wanted to draw it with Selvala before completing our search for a land? We could decide we didn't want that top card, finish our search, then shuffle, leaving a potentially different card on top. You can see how this would be a problem.

However, keep in mind that intent is pivotal here. A Magic player who ends up in this scenario purely by accident, never having considered how they might gain an advantage from the interaction, is not cheating. But now that you know about this, if you ever try it, then you are cheating. You're welcome!

Perhaps the worst of it is that Selvala could have avoided this fate. A simple functional errata appended to her Parley ability would nip this in the bud: "Activate only as an instant." This would enforce the already popular mana floating for her ability and forever render any future criminal activity impossible. At the time of writing, there are only 1271 Selvala, Explorer Returned decks, and just 1.18% of them have included Panglacial Wurm. Let's get the first number up, and the second number down to 0%!

So, have you called BS? To the readers, what are some Magic interactions that blow your mind, or that just downright shouldn't exist? Let me know in the comments, and thank you for reading my debut article! See you next time!

I'm a Magic judge and EDH enthusiast who loves rules interactions, group hug, and table politics. My other projects include the Commander Spellbook and the Social Contract EDH podcast.