<p>Psychosis Crawler won't die during the resolution of Day's Undoing.  Toughness check is done as a state-based action.  State-based actions are checked after each spell/trigger is done resolving.</p>
<blockquote>
<p>704.3. Whenever a player would get priority (see rule 116, “Timing and Priority”), the game checks for any of the listed conditions for state-based actions, then performs all applicable state-based actions simultaneously as a single event. If any ...</p>
<p>704.4. Unlike triggered abilities, state-based actions pay no attention to what happens during the resolution of a spell or ability.</p>
</blockquote>

CC BY-SA 3.0
2017-07-12T22:28:19.710Z
Re "*State-based actions are checked after spells/triggers are done resolving.*", That makes it sound like they are performed after all spells/abilities on the stack are done resolving, but that's wrong. I suggest the following alternate wording: State-based actions aren't checked during the resolution of a spell or ability; they are only checked when a player would get priority.
ikegami
CC BY-SA 3.0
2017-07-12T22:34:20.443Z
Note that triggers, on the hand, are constantly checked, if permanent had an ability that triggered "whenever a creature is reduced to zero toughness", it would trigger.
ikegami
CC BY-SA 3.0
2017-07-19T06:54:38.967Z
@ikegami Just had a brain wave, does that mean that I wouldnt have to untap Niv mizzet because during Days undoing, the 7 card draw would initiate the combo with Curiosity again right? Essentially meaning I could cut  Dramatic Reversal out of this situation?
ThunderToes
CC BY-SA 3.0
2017-07-19T06:59:45.910Z
@ThunderToes, Correct.
ikegami
CC BY-SA 3.0
2017-07-19T07:01:21.530Z
Wonderful. Less manna to enable this then :)
ThunderToes
CC BY-SA 3.0
2017-07-12T13:20:55.067Z
2017-07-13T13:50:31.637Z
2020-06-17T09:01:24.697Z
JonTheMon
<p>Okay, so I have a commander deck that allows me to draw my entire library and I stumbled upon a strange situation.</p>

<p>This is the chain of events I want to happen:</p>

<ol>
<li>Tap <a class="mtg-autocard" target="_blank" rel="noreferrer" href="http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bNiv-Mizzet%2c%20the%20Firemind%5d">Niv-Mizzet, the Firemind</a> with <a class="mtg-autocard" target="_blank" rel="noreferrer" href="http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bCuriosity%5d">Curiosity</a> attached to form an
infinite draw combo.</li>
<li>Cast <a class="mtg-autocard" target="_blank" rel="noreferrer" href="http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bPsychosis%20Crawler%5d">Psychosis Crawler</a></li>
<li>Cast <a class="mtg-autocard" target="_blank" rel="noreferrer" href="http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bDay%27s%5d%2b%5bUndoing%5d">Day&#39;s Undoing</a> to return my hand and graveyard to my library and draw 7, reactivating the combo with <a class="mtg-autocard" target="_blank" rel="noreferrer" href="http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bNiv-Mizzet%2c%20the%20Firemind%5d">Niv-Mizzet, the Firemind</a> and <a class="mtg-autocard" target="_blank" rel="noreferrer" href="http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bCuriosity%5d">Curiosity</a></li>
</ol>

<p>My question is, during the resolution of Day's Undoing, Psychosis Crawler's power and toughness will be reduced to 0 before I draw my 7 cards (as far as I'm aware?). Does this mean he will die before I activate the draw combo again to win?</p>

CC BY-SA 3.0
2017-07-12T13:39:00.233Z
Is the Niv-Mizzet part of the question really necessary?
JonTheMon
CC BY-SA 3.0
2017-07-12T13:49:17.643Z
@JonTheMon To me it adds a bit of context to why I am using this combo
ThunderToes
CC BY-SA 3.0
2017-07-12T14:25:37.350Z
But the actual interaction you're looking at is Psychosis Crawler and Days Undoing.  And even that can be boiled down to Crawler and any wheel effect.
JonTheMon
CC BY-SA 3.0
2017-07-12T15:08:07.577Z
I'm confused... wouldn't you have won the game after step 1, before you ever get a chance to cast any of the other things?
GendoIkari
CC BY-SA 3.0
2017-07-12T15:13:46.050Z
Or is the issue simply that the Niv + Curiosity combo can only deal about 85-90 damage before you run out of cards to draw, which wouldn't be enough in a Commander game to kill all opponents?
GendoIkari
CC BY-SA 3.0
2017-07-13T09:21:19.937Z
@GendoIkari Thats the problem. in a multiplayer game i cant kill everyone before I Deck myself and lose. I will be looking for a Laboratory Maniac to further prevent that eventuality. however with Psychosis it deals damage to all opponents giving another possible win con. I may also rely on Fabricate and other tutors to make sure i have Psychosis on the field in the first place.
ThunderToes
<magic-the-gathering><mtg-commander>
Does Psychosis Crawler die in the middle of Days Undoing?
ThunderToes
# Does Psychosis Crawler die in the middle of Days Undoing?

(Asked by: username_0 on 2017-07-12)

Okay, so I have a commander deck that allows me to draw my entire library and I stumbled upon a strange situation.

This is the chain of events I want to happen:

1. Tap [Niv-Mizzet, the Firemind](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bNiv-Mizzet%2c%20the%20Firemind%5d) with [Curiosity](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bCuriosity%5d) attached to form an
   infinite draw combo.
2. Cast [Psychosis Crawler](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bPsychosis%20Crawler%5d)
3. Cast [Day's Undoing](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bDay%27s%5d%2b%5bUndoing%5d) to return my hand and graveyard to my library and draw 7, reactivating the combo with [Niv-Mizzet, the Firemind](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bNiv-Mizzet%2c%20the%20Firemind%5d) and [Curiosity](http://gatherer.wizards.com/Pages/Search/Default.aspx?name=%2b%5bCuriosity%5d)

My question is, during the resolution of Day's Undoing, Psychosis Crawler's power and toughness will be reduced to 0 before I draw my 7 cards (as far as I'm aware?). Does this mean he will die before I activate the draw combo again to win?

**Tags:** magic-the-gathering, mtg-commander

> **Comments:**
> **username_1**: Is the Niv-Mizzet part of the question really necessary?  
> **username_0**: @username_1 To me it adds a bit of context to why I am using this combo  
> **username_1**: But the actual interaction you're looking at is Psychosis Crawler and Days Undoing.  And even that can be boiled down to Crawler and any wheel effect.  
> **username_2**: I'm confused... wouldn't you have won the game after step 1, before you ever get a chance to cast any of the other things?  
> **username_2**: Or is the issue simply that the Niv + Curiosity combo can only deal about 85-90 damage before you run out of cards to draw, which wouldn't be enough in a Commander game to kill all opponents?  
> **username_0**: @username_2 Thats the problem. in a multiplayer game i cant kill everyone before I Deck myself and lose. I will be looking for a Laboratory Maniac to further prevent that eventuality. however with Psychosis it deals damage to all opponents giving another possible win con. I may also rely on Fabricate and other tutors to make sure i have Psychosis on the field in the first place.  

---

## 1 answers

### Answer by username_1 on 2017-07-12. Score: 8 | Accepted answer

Psychosis Crawler won't die during the resolution of Day's Undoing. Toughness check is done as a state-based action. State-based actions are checked after each spell/trigger is done resolving.

> 704.3. Whenever a player would get priority (see rule 116, “Timing and Priority”), the game checks for any of the listed conditions for state-based actions, then performs all applicable state-based actions simultaneously as a single event. If any ...
>
> 704.4. Unlike triggered abilities, state-based actions pay no attention to what happens during the resolution of a spell or ability.

> **Comments:**
> **username_3**: Re "*State-based actions are checked after spells/triggers are done resolving.*", That makes it sound like they are performed after all spells/abilities on the stack are done resolving, but that's wrong. I suggest the following alternate wording: State-based actions aren't checked during the resolution of a spell or ability; they are only checked when a player would get priority.  
> **username_3**: Note that triggers, on the hand, are constantly checked, if permanent had an ability that triggered "whenever a creature is reduced to zero toughness", it would trigger.  
> **username_0**: @username_3 Just had a brain wave, does that mean that I wouldnt have to untap Niv mizzet because during Days undoing, the 7 card draw would initiate the combo with Curiosity again right? Essentially meaning I could cut  Dramatic Reversal out of this situation?  
> **username_3**: @username_0, Correct.  
> **username_0**: Wonderful. Less manna to enable this then :)  

---

