[5E] Interrupting a Spellcaster via Ready Action

[Nickolaidas]

Initiative Order:

1. PC Fighter
2. Grimlock
3. PC Wizard
4. Mind Flayer Arcanist
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"DM: PC Fighter, what do you do?

PC Fighter: I grab my spear and ready the following action: The second I see the Mind Flayer Arcanist attempting to cast a spell (using Verbal or Somatic Components), I throw my spear at the Mind Flayer's chest.

Grimlock: The monster dashes towards the PC Wizard and ends its movement right in front of him.

PC Wizard: I cast shield on myself.

DM: Magical energies surround you and you can feel more protected against enemy attacks. The Mind Flayer Arcanist moves its hands and makes hissing sounds as it is about to cast a spell …."

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Alright, so now what?

I've checked a few websites which talk about this, and there are quite a few opinions:

A) Some think that the Mind Flayer must FIRST cast the spell, and THEN the fighter throws his spear.

B) Others say that the fighter must FIRST throw the spear and THEN the Mind Flayer (if still alive) casts the spell.

Others say that in case of B):
1] If hit, the Mind Flayer must make a Concentration check or lose the spell …

or 2] If hit, the Mind Flayer must ONLY make a Concentration check if he was casting a spell which requires concentration to maintain.

Personally, I'm on camp B) and 2], but I want to hear your opinions as well. Do you fall under any of those categories? Or do you do something else entirely in situations like this?

I chose B) instead of A) because in case A), there's no reason for the PC Fighter to ready that particular action since he ALREADY plays BEFORE the Flayer via initiative and basically by choosing A) the Fighter allows the Mind Flayer to cast first and get hit second, instead of being hit on the Fighter's turn and if killed, never casting a spell in the first place.

Now I chose 2] instead of 1], because a caster ALWAYS rolling for concentration check any time he gets hit via Ready Action risks me rendering a caster useless. All I have to do is having 2-3 fodder monsters ready their action to hit a PC Caster anytime he's about to cast a spell and every single round the caster may have to roll THREE concentration checks or never actually manage to cast the simplest of cantrips. Option 2] on the other hand can be better because the caster can still cast basic spells without running the risk of losing them, and the risk of being KO'd before casting still exists.

Thoughts?
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[DND_Reborn]

So 2B or not 2B? That is the question???

Seriously though, I mostly agree with your take on it and that is how we play, except was play with [1], casters hit by readied actions must always make a Concentration check or the spell is ruined. It makes casting harder, but otherwise it is too powerful IMO.

. I don't recall anything in the rules about it, but since the readied action was about the instant the Mind Flayer shows signs of casting, etc. However, I would also have the PC Fighter have to recognize the spell as such. The Mind Flayer, seeing the PC Fighter waiting, could just wave his hands and make squishy-gurgling noises, the spear is thrown, and then actually casts the spell.

 

[MarkB]

It's pretty simple. "You can take your action right after the trigger finishes." If the trigger is someone casting a spell, you take your action after they cast the spell.

 

[DND_Reborn]

It's pretty simple. "You can take your action right after the trigger finishes." If the trigger is someone casting a spell, you take your action after they cast the spell.

But that wasn't the triggering event, the triggering event was the Mind Flayer moving or "speaking" (somatic or verbal) while casting its spell. I understand your point, but 5E has really made it very difficult for spells to not be disrupted during the casting process since most are casting times of simply 1 action.

 

[Nickolaidas]

It's pretty simple. "You can take your action right after the trigger finishes." If the trigger is someone casting a spell, you take your action after they cast the spell.

So basically the only reason a PC would ready an action to hit a spellcaster is to break his concentration IN CASE he casts a spell with ongoing duration.

 

[MarkB]

But that wasn't the triggering event, the triggering event was the Mind Flayer moving or "speaking" (somatic or verbal) while casting its spell.

And when does it finish moving its hands and speaking its verbal components? After it finishes casting.

 

[MarkB]

So basically the only reason a PC would ready an action to hit a spellcaster is to break his concentration IN CASE he casts a spell with ongoing duration.

Pretty much. The Ready action's utility was significantly reduced in 5e, with the only major compensation being that it doesn't change your initiative position anymore (so, in the OP's example, if the Fighter attacks the Mind Flayer with his readied action, he'll then be able to take his turn immediately afterwards, before the Grimlock, rather than having to wait until just before the Mind Flayer's next turn).

 

[Nickolaidas]

The way I see it, an attack used as a readied action - which is used as a reaction, acts like the counterspell (which is ALSO a reaction) - it is done before the spell (which is counterspelled) can have any effect.

However, while counterspell is a sure thing (unless the spell is quite a few lvls above its league), the physical attack only does damage and can only prevent the spell in case it kills the spellcaster or if the spellcaster casts a concentration spell AND fails the concentration check … so I don't think that physical attacks used as readied actions to hit a spellcaster run the risk of rendering counterspell or spellcasting useless.

 

[Nickolaidas]

Pretty much. The Ready action's utility was significantly reduced in 5e, with the only major compensation being that it doesn't change your initiative position anymore (so, in the OP's example, if the Fighter attacks the Mind Flayer with his readied action, he'll then be able to take his turn immediately afterwards, before the Grimlock, rather than having to wait until just before the Mind Flayer's next turn).

Thanks for the feedback! You too, dnd4vr!

 

[Swarmkeeper]

And when does it finish moving its hands and speaking its verbal components? After it finishes casting.

But finishing the spell need not be the trigger for the Readied Action.

PC Fighter: if the Flayer starts moving its hands or speaking words to cast a spell, I spear it.