State-based actions, or SBAs for short, are the game's janitorial service. They work in the background and clean up things like dead creatures, players who should lose, and so on. This week, let's review SBAs and cover some common interactions that might come up involving them.
There are eighteen SBAs that apply to every game of Magic, and another six that are format-specific.
Any time a player would get priority, the game checks to see if any SBAs need to happen, then performs all applicable SBAs simultaneously. If SBAs are performed, the game checks them again. This keeps happening until we get a check where no SBAs need to happen, after which the appropriate player gets priority.
Because the game checks SBAs when a player would get priority, this means it doesn't check in the middle of a spell or ability resolving. For example, if I control Psychosis Crawler and cast Wheel of Fortune, my Crawler doesn't die. Even though it briefly has 0 toughness while my hand is empty, it has greater than 0 toughness the next time SBAs are checked after the Wheel resolves.
The Ones That Make Someone Lose
Obviously, players die if they are killed. A few different SBAs ensure that a player who should lose the game actually does. First, if a player or team has 0 or less life, they lose. They can also lose from accumulating too many poison counters. In most formats, the threshold is 10 poison counters; in Two-Headed Giant, 15.
A player loses if they tried to draw from an empty library since the last time SBAs were checked. Note that in order for this to apply, a player needs to actually try to draw a card. If they replace that draw with something like Abundance, they didn't attempt to draw and they won't lose.
Finally, a player loses if they've been dealt 21 damage by the same commander in a Commander game. Notably, this means a player can die to their own commander if it's stolen by something like Agent of Treachery. Partner commanders track their damage separately. Double-faced commanders like Plargg, Dean of Chaos // Augusta, Dean of Order count as one commander; damage from Plargg and damage from Augusta accumulate together.
The Ones That Make Stuff Die
A lot of SBAs function to keep the battlefield clear of things that ought to not be there anymore.
Not So Tough
A creature with 0 or less toughness is put into its owner's graveyard. Note that the creature isn't "destroyed," so regeneration can't save it. This most often comes up with effects like Dead Weight's or -1/-1 counters.
This also matters if one creature buffs another one. Let's say I control Ashenmoor Liege and a smattering of 1/1 red Devil creature tokens. Because of the Liege, the tokens are currently 2/2. If my opponent casts Ad Nauseam, the first SBA check says "Hey, that Liege needs to die." Right after the Liege dies, the Devil tokens die too, because without the buff from the Liege they're base 1/1 creatures with -1/-1 until end of turn.
If a creature has more damage marked on it than it has toughness, it is destroyed by lethal damage. This is probably the most commonly applied SBA and the source of That One Tarmogoyf Question. For those that aren't familiar:
I control Tarmogoyf. Graveyards have creature and land cards, so Tarmogoyf is 2/3. My opponent Lightning Bolts Tarmogoyf. What happens?Like half of Modern players back in 2011
The Tarmogoyf lives! The game doesn't check SBAs until just after Bolt resolves. At that point, Bolt is in the graveyard, so Tarmogoyf has a new card type to eat. I have a 3/4 with 3 damage marked on it, and my opponent just wasted their Bolt.
If a creature has been dealt damage by a source with deathtouch since the last time SBAs were checked, it's destroyed. Note the added emphasis. If I attack with Ambush Viper and my opponent blocks with Darksteel Sentinel, I mark two damage on the Sentinel and it survives. If I then cast Dress Down so that the Sentinel loses abilities, it just... sits there. It's a 3/3 with 2 damage marked on it, but because the game checked SBAs in between the damage being dealt and the Dress Down resolving, the damage is no longer "deathtouch damage."
Planeswalked to Death
If a planeswalker has 0 loyalty, it goes to its owner's graveyard. Simple enough!
If an Aura is attached to something it can't legally enchant or is attached to nothing, it goes to the graveyard. Importantly, it goes directly from its current state to the graveyard; it doesn't unattach first.
Everybody Wants to Rule the World (Type)
If multiple permanents have the supertype world, the newest one wins and the others go to the graveyard. Most players probably won't ever have to worry about this SBA outside of Commander.
Legen - Wait For It - dary
Similar to the world rule, There Can Be Only One. If the same player controls multiple legendary permanents with the same name, they choose one to keep and put the other ones in the graveyard. Importantly, the player doesn't "sacrifice" those other permanents. An effect like Mayhem Devil's doesn't trigger.
The Ones About Counters
Exactly one card, Rasputin Dreamweaver, can't have more than seven dream counters on it. Luckily, this little idiot has his very own SBA that says if he somehow has more than seven dream counters, any excess counters are removed. Sorry, proliferate fans!
Another, better, more widely applicable SBA says that if a permanent has both +1/+1 and -1/-1 counters, they obliterate each other in equal amounts until only one kind is left. That is, a creature with 4 +1/+1 counters and 3 -1/-1 counters will be left with a single +1/+1 counter after this SBA.
The Ones About Ceasing to Exist
If a token is anywhere except the battlefield, it ceases to exist. It's worth noting that tokens do go to whatever zone first. For instance, a Treasure token goes to the graveyard before it poofs out of existence. I mention this mostly because Treasures are very pushed in Streets of New Capenna and Viridian Revel exists.
Copies of spells and cards can't exist outside of the zones the game expects them to be in.
If a copy of a spell is anywhere but the stack, it ceases to exist. I can't get a copy of Capsize back in my hand just because I paid its buyback cost.
Similarly, if a copy of a card is anywhere but the stack or battlefield, it ceases to exist. I can't get cute with God-Eternal Kefnet and choose to make a copy of a card but not cast it. That copy would vanish right after the triggered ability resolves.
The Ones About Unattaching
Some SBAs deal with attachment issues. So do some therapists.
If an Equipment or Fortification (thanks, Darksteel Garrison!) is attached to an illegal permanent or to a player, it becomes unattached.
If a creature is attached to something, or if a permanent that is not an Aura, Equipment, or Fortification is attached to something, it becomes unattached. The former clause means if I activate Karn, Silver Golem targeting an opponent's Brass Knuckles, the Knuckles unattach. The latter says that if I Song of the Dryads an Aura / Equipment / Fortification, it stops being attached because I made it a land.
Note the contrast between these and the illegal Aura SBA. Auras go to the graveyard, but these do not. They stop being attached to what they were attached to, but they never leave the battlefield.
The One About Sagas
Most Modern players have either taken advantage of this SBA or seen an opponent take advantage of it. A player has to sacrifice their Saga if it has lore counters on it greater than or equal to its final chapter number and it isn't the source of a chapter ability that's still on the stack.
This means that if I control Urza's Saga, I can activate one of its abilities while the 3rd chapter's ability is on the stack. I don't have to sacrifice it until after its final chapter ability resolves.
This SBA also helps explain why a Blood Moon'd Urza's Saga gets sacrificed right away. Since the Saga loses all of its abilities, it has no final chapter number, so its final chapter number defaults to 0. Since 0 is equal to 0, the Saga goes "Oh no, I pine for the fjords" and promptly goes to the graveyard.
The One About Dungeons
Much like the Saga SBA, the dungeon SBA wants to get rid of the dungeon as soon as it's no longer relevant. If I'm in the bottom room of a dungeon and the dungeon doesn't have a trigger on the stack, the dungeon leaves the game.
The Ones About Variant Formats
I already touched on the commander damage rule and the Two-Headed Giant rules that make someone lose, so let's not revisit those.
The Last One About Commander
About a year ago, the Commander Rules Committee changed how the commander zone change rule worked. Before, if a commander would die or go to exile, I could put it into the command zone instead. This meant that "dies" triggers wouldn't happen (sorry, Child of Alara), but it also meant that if someone hit my commander with Banishing Light the commander would return from the command zone.
Now, there's a shiny new(ish) SBA that says if a commander is in a graveyard or in exile and it was put there since the last SBA check, its owner can put it in the command zone. This changes several interactions that players previously knew. As mentioned earlier, now if someone hits my commander with Banishing Light, and I put it in the command zone, it will not come back when Banishing Light leaves the battlefield. The commander went to another zone, so Banishing Light's effect lost track of it.
Similarly, if I sacrifice my commander, my opponent can't steal it with It That Betrays unless I really, really want them to. If I put my commander in the command zone, it's no longer in the same zone as it first went to. It That Betray's trigger can no longer find it.
The Ones about Planechase and Archenemy
I grouped these together because the game handles them pretty similarly.
If a scheme isn't the source of a trigger on the stack, it goes to the bottom of the scheme deck.
If a phenomenon isn't the source of a trigger on the stack, the planar controller planeswalks.
That's all for this (very long) week. Next week should be all about Streets of New Capenna if the new comprehensive rules come out in time, so don't forget to stop by!
Question of the week: How many SBAs did you actually know existed before reading this article?