When the Shocking Grasp cantrip hits, can it trigger the Tempest cleric's Wrath of the Storm reaction?

Question

The Tempest Domain cleric's Wrath of the Storm feature description says (PHB, p. 62):

When a creature within 5 feet of you that you can see hits you with an attack, you can use your reaction to cause the creature to make a Dexterity saving throw. The creature takes 2d8 lightning or thunder damage

The Shocking Grasp cantrip's description says (emphasis mine):

On a hit,the target takes 1d8 lightning damage, and it can’t take reactions until the start of its next turn.

Can Wrath of the Storm be a reaction on Shocking Grasp itself? In what order spells effects are supposed to work?

1. Shocking Grasp hits
2. Wrath of the Storm triggers on hit
3. Shocking Grasp deals damage
4. Shocking Grasp sets a condition "can’t take reactions"

or

1. Shocking Grasp hits
2. Shocking Grasp deals damage
3. Shocking Grasp sets a condition "can’t take reactions"
4. Wrath of the Storm doesn't do anything because it's a reaction

Answer 1

It comes down to a DM ruling

Unfortunately, the rules aren't 100% clear on the issue of when exactly a reaction occurs, and Jeremy Crawford/Mike Mearls both seem to leave it to DM ruling for other reactions. (note that Crawford says "I have it happen after" as opposed to speaking in a rules-authoritative voice). The PHB errata also does not clear up this issue.

However, one reaction that occurs on being hit with an attack and that could potentially negate the attack is the Shield spell. Notably, it specifies that the +5 AC added can negate the triggering attack, and functions against other attacks until the start of your next turn.

Given that shield specifically calls this out, and other reactions-to-hit like Wrath of the Storm don't, you might infer that the hit generally takes place unless some specific rule negates it, and there is no specification in Wrath of the Storm. Other effects that can negate attacks like the Protection fighting style use the word "attack" instead of "hit". So in this case, you still get hit by the attack and suffer any consequences of the attack. Those consequences include taking damage and not being able to take reactions. Then the Wrath of the Storm reaction trigger occurs (being hit with an attack), but you can't use it. This effectively eliminates a corner case where, otherwise, you would get hit, but Wrath of the Storm kills the target before you take damage/suffer effects of the attack.

However, a DM may still rule otherwise, and it would be difficult to make a RAW argument opposing it (provided your DM was interested in hearing such an argument in the first place).

Answer 2

The way I see it: No

you can use your reaction

This does not imply that you didn't have one to begin with. It just allows for you to use your reaction in the form of Wrath of the Storm.

can’t take reactions

This simply takes away the option to do ANY reaction. Therefore there is no reaction for the person to use for Wrath of the Storm.

example:

1. I have an apple in my hand.
2. I have the ability to change all apples in my hands to pears.
3. Someone takes away my apple.
4. Can I still change it into a pear? No.

As for WHEN you use your reaction. It's irrelevant to this situation, because Wrath of the Storm's description says:

When a creature within 5 feet of you that you can see hits you with an attack.

This means that even if you could use a reaction before the hit landed, you can only use Wrath of the Storm after the hit, which is when the reaction is "gone".

If you say that the "hit" and "being hit" happen at exactly the same time, so that you could technically still do the reaction, you are technically right but mechanically incorrect.

The moment you are struck, the effect that removes your reaction is in effect. If you were to use the exact nanosecond to react with your ability, it would need to be done within a time of 0 seconds. I believe it's unrealistic to do a reaction within 0 seconds, even in a format where reality often does not apply. Unless you can somehow bend time and space, the answer should still be No.

Answer 3

I generally agree with Migz's answer here, but will approach it a different way.

Page 194 of the PHB shows the structure of an attack:

1. Choose a target. ...
2. Determine modifiers. ...
3. Resolve the attack. You make the attack roll. On a hit, you roll damage, unless the particular attack has rules that specify otherwise. Some attacks cause special effects in addition to or instead of damage.

It's clear here that the damage, and the special effects that come with it, comes with the hit. In other words, you can't get hit and not get damaged (and effected).

So, in this case, Shocking Grasp's effect of taking away your reaction on a hit takes effect before you could even react with Wrath of the Storm, as intended of the cantrip. In the same spirit, you can't use Wrath of the Storm if the hit would bring you down to 0 Hit Points.

Answer 4

All signs point to no.

---

The Dungeon Master's Guide, p.252 says:

Adjudicating Reaction Timing

...sometimes the timing of a reaction can be difficult to adjudicate. Use this rule of thumb: follow whatever timing is specified in the reaction's description. For example, the opportunity attack and the shield spell are clear about the fact that they can interrupt their triggers. If a reaction has no timing specified, or the timing is unclear, the reaction occurs after its trigger finishes, as in the Ready action.

Note that Jeremy Crawford has answered a very similar question before (link):

Mage Slayer doesn't specify timing, and a reaction without special timing occurs after its trigger (DMG, 252).

@JeremyECrawford A creature casts shocking grasp on a Mage Slayer PC. If the PC reacts to the spell being "cast," does he get his reaction?

For the sake of completeness, this timing rule is also referenced in the Sage Advice compendium, this time with regards to the Sentinel feat:

Does the attack granted by the third benefit of the Sentinel feat take place before or after the triggering attack?

The bonus attack takes place after the triggering attack. Here’s why: the feat doesn’t specify the bonus attack’s timing, and when a reaction has no timing specified, the reaction occurs after its trigger finishes (DMG, 252). In contrast, an opportunity attack specifically takes place before its trigger finishes—that is, right before the target creature leaves your reach (PH, 195).

---

So, since Wrath of the Storm doesn't have any clear indication that it can interrupt its trigger, the reaction takes place after Shocking Grasp. The target's reaction has already been taken away by that point.