[RPG] Can Polymorph end spells that require the target to be humanoid


There are several spells that require the target to be "humanoid" such as Hold Person, Dominate Person, etc.

However, if the target is Polymorphed after that spell has been successful, then what happens?

Does the change in form to Beast end the spell effects? Does it suppress the spell until the correct form returns? Does it do something else?

Best Answer

RaW, unclear. Unofficial Crawford rulings, the spell is suppressed.

There have been conflicting answers about the topic on Twitter. On one hand, you have Mearls saying the spell would stick:

Nope, restriction applies to targeting - sticks after successful cast

On the other, you have Crawford saying it doesn't stick:

In #DnD, the exceptional trumps the general. (No longer being a valid target trumps condition carryover.)

However, as of the 2019 Sage Advice Compendium release, only the rulings in the SAC are "official"; previously, Jeremy Crawford could tweet "official rulings", but now the SAC says Crawford's tweets are simply "often a preview of rulings that will appear" in the SAC.

The SAC does not mention what happens in this situation. In other words, RaW does not specify what happens.

My favorite ruling about this (makes for fun interactions at the table) is that the spell is suppressed while the target is invalid. It comes from Crawford:

There's no rule governing what happens when a valid spell target temporarily becomes an invalid target. A good rule of thumb is that the spell is suppressed while the target is invalid.

It agrees with other answers about Dominate Beast, for example. Another answer has a different opinion, that spell wording has subtle implications, but I'm not sure the wording is different on purpose, seeing as even Crawford doesn't know about it.

Suppressing the spell when the target is invalid also makes fun interactions at the table, and lets your players get creative. If your poor low-HP friendly Bard is being Dominated by some arcane evil Wizard that has acquired some nasty spell-immunity shields, your friendly Wizard can cast Polymorph or True Polymorph to turn your ally into a T-Rex, which breaks the Dominate Person (as the Bard is now a Beast, and not a Humanoid), and also lets your friendly Bard go on some sort of raging bloody rampage.

In the end, it comes down to DM fiat, and there is no RaW answer.