Can you hold Plane Shift on an unwilling creature until they touch you to skip the melee spell attack?

Question

One of my players uses the Plane Shift spell quite regularly in battle to get rid of unwanted opponents. With the ready action and the holding of a spell being a thing, the question has come up, whether he could ready the Plane Shift spell as an action and wait for the opponent to attack him as the trigger to release the spell.

You can use this spell to banish an unwilling creature to another plane. Choose a creature within your reach and make a melee spell attack against it. On a hit, the creature must make a Charisma saving throw. If the creature fails this save, it is transported to a random location on the plane of existence you specify.

The question that came up is whether he would still have to make a melee spell attack as described in this part of the spell. The reasoning of my player is, that if a dragon bites him, he is technically already touching him or he could simply reach out to "boop the dragon's snoot" since he has his teeth sunk into his arm and therefore cannot really dodge his hand.

The first time he did this I let it slide per "Well, guess you outsmarted me this time. Sure go for it" - but I feel like in the long run it might be a bit tricky to have a player forego a part of the spell. It doesn't seem to me that this is how it is intended. A fighter would also still have to roll if he can hit the target, but at the same time Plane Shift is still connected to a Charisma Saving Throw the target has to fail so I am unsure how to handle it per RAW/ RAI.

Answer 1

No.

The fact that Plane Shift requires a saving throw from the target is irrelevant here, as it is an additional drawback specific to this spell. You could Ready any melee spell attack in a similar way and the flow of the scenario should be the same.

The rules don't mention any benefits for choosing to cast your spell in this way, therefore there's no reason to assume it should be easier to hit. A touch spell (or any attack) is not an automatic hit even on a petrified or a paralyzed creature, even though it could be realistically explained that it is impossible for them to dodge. You could invent many reasons as for why it might miss, such as reflecting off the dragon's scale, it pulling away too quickly, and biting the character from behind or in such a way that it constrained their ability to "boop its snoot". It's pretty safe to say skipping the attack roll is not RAW or RAI.

Additionally, remember that the readied action is taken after the specified trigger occurs and a spell you're holding is considered concentration. If the player stated something along the lines of "If the dragon bites me, I will cast Plane Shift on it", then (provided the dragon hit them) you roll damage first and they have to roll a constitution saving throw to see if they can maintain it. If they fail, or if the trigger for the reaction doesn't occur before the start of their next turn, the spell slot is expended with no effect.

You could give them advantage

In the future, if you feel a player's solution to a problem is appropriate and want to reward that, the right tool for the job would be granting them advantage on the roll. Conversely, for bad solutions you can impose a disadvantage.

Answer 2

The attack is mandatory

The spell is worded very precisely in order of operations:

• Choose a creature within range.
• Roll a melee spell attack.
• On Hit: roll a charisma save.
• On Fail: banish to another realm.

Nothing in the spell allows you to bypass the melee spell attack roll. Without the attack roll, there is no hit and thus no charisma save and thus can't be a banishment.

Delaying the action

Delaying an action does not alter that block in favor of the PC. On the contrary, it puts three more steps in between choosing a target and rolling the attack: First, the PC marks the appropriate spell slot as spent after their action declaring the delay, and are now concentrating on the spell. Next, the dragon needs to attack them with the declared trigger, and finally, the PC has to make their constitution save to maintain concentration before they can roll their spell attack, as the triggering action is fully completed before the triggered one starts. If either the dragon does not attack, or the roll for concentration fails, the spell is gone for nothing.

Nothing in the rules as written gives any bonus or benefit on the situation by default but the option to grant Advantage.

Why I wouldn't grant Advantage for such situations on a whim

However, I am not convinced the tactic should grant Advantage in a manner that is not clearly non-precedential.

If granted without such note*, it can set a precedent for the action of delaying always granting Advantage. If you grant Advantage on the melee spell attack, fairness dictates to also grant Advantage for similarly waiting for the opponent to attack them first with any other weapon too. That could impact the balance of the game, which needs to be thought about first. Such a widespread decision should not be made on a whim and needs further investigation before adding it as a houserule. Among other things one needs to look into things like using the Advantage for setting it up to trigger other feats or abilities (such as sneak attacks), how it impacts other classes (e.g. the spellcasters with concentration rolls, martial classes losing extra attacks), the action economy (e.g. reactions or lack thereoff), range and movement (such as the possibilities to mitigate the range or reach of weapons), and the cost of losing the readied action. Only after carefully weighing all factors a houserule on readied action for Advantage should come down, which then is used for every player, regardless of class.

_{* - Such a note could be "For this occasion..." or similar. Pretty much anything that clearly states that this occasion of Advantage stands on the merits of the situation at hand, and can not be used as precedent to badger in Advantage later.}

Answer 3

Mechanically, Plane Shift isn't a mere touch

You have to hit the target's AC. 24 constitution Barbarian with 8 dex has 16 AC, and next to none of it is because they are good at dodging.

Just like a weapon attack, Plane Shift requires you touch a particularly vulnerable part of the target - ie, a hit against AC.

The caster needs to make a concentration save

Holding a spell ready involves actually casting it, concentrating on the spell as you hold it, and releasing it as a reaction. Any damage you take requires a concentration check. If the trigger fails to happen, the spell is lost (by RAW, but sometimes I'll let a PC continue to hold it more than 1 round by expending an action again; if this continues, I'll require increasing concentration checks).

Advantage is appropriate

Granting advantage on attack rolls when the PC has a tactical advantage is a standard tool in the DM's toolbox. I'd also let a PC with a sword get advantage on attacking a dragon if they wait until after they are bitten. In both cases, the readied action won't go off if the Dragon doesn't act as predicted.

If the readied action is less specific than something like "I attack the dragon after it bites me by stabbing it in the nostril", then the advantage goes away.

So, being generous, it would go like this:

1. The PC casts plane shift and holds their action
2. The dragon bites the PC. It hits.
3. The PC makes a concentration check or loses the spell.
4. The PC uses their reaction to the bite, and makes a spell attack at advantage on the dragon.
5. If it hits, the dragon must make a charisma saving throw
6. If the trigger doesn't go off (no bite), I'd let them make a DC 10+5/round concentration check to continue holding the spell as an action. (This is not the rules, just being generous)

Answer 4

As others have said. No it would not let them bypass a melee spell attack. Because that's part of the spell.

Holding their action would require the caster to concentrate on the spell and to have it trigger within a round (before it's the casters turn again).

So it would be:

1. PC casts the spell using their action. They are now concentrating on a spell

2. Dragon bites (if that's the trigger) and hits. Roll damage as normal.

3. The PC has taken damage, while they are concentrating. They need to make a constitution saving throw. The DC is equal to half the damage they just took.

4. If the PC manages that, they now get to do a melee spell attack with their reaction on the dragon. If that hits, the Dragon does the saving throw....

Additional info: Pay attention to the trigger declared for the held action. If they specify "when the dragon BITES me". And the dragon claws them in the face or tail attacks them for example, this would NOT trigger the held action.

See concentrating under "taking damage"

https://roll20.net/compendium/dnd5e/Spells#content

And also see Combat under "Ready"

https://roll20.net/compendium/dnd5e/Combat#content