Our goblin druid posed a question today which made our DM bluescreen:

"If I turned into a giant toad, swallowed a Medium-sized creature whole, and then turned back, what happens?"

The goblin druid is a Small creature, and the giant toad is a Large creature. The creature being swallowed is Medium-sized.

This is essentially the inverse of this question, though not quite a duplicate because it's the eating creature doing the shapeshifting rather than the eaten one. Closely related to this question, with the primary difference being wildshape by a willing druid vs polymorph of an unwilling monster.

When a target of an effect ceases to be a valid target it is no longer affected

A giant toad can swallow a creature, your druid cannot - as per the effect, I mean. Obviously, the druid can swallow things that a goblin could swallow - things I don't want to think about.

As the druid transforms from giant toad to goblin the swallowing ends. Feel free to describe how this happens in as much nauseating detail as you like.

Lack of specific rules means DM has to decide.

But let's help him by considering options, shall we?

1. If the creature is harmed, but the druid is not:
   
   Whether you inflict massive damage, or just decide the creature disappears to nothingness - this means the Giant Frog becomes a killing machine. A level 4 moon druid probably does not need that kind of help.




2. If the druid is harmed, but the creature is not:
   
   Then swallowing a creature becomes very risky. It removes the Giant Frog's main ability, and encourages the druid to stick to other combat forms. Bears and wolves. Yawn.




3. If both the druid, and the the creature are harmed (such as suggested here):
   
   Then swallowing a creature becomes a valid, sacrificial move - that may have its narrative interest. However, the DM should ensure it can't be exploited too easily: killing a BBEG with that method only to have the druid back on his feet with a healing kit should feel like cheating.




4. If neither the druid, nor the the creature is harmed:
   
   Game continues as usual, with many messy descriptions but few mechanical impacts.

Obviously #4 seems the most safe and sensible option to me - but #3 may lead to interesting situations if handled properly. This is only opinion though.

On a side note: in-game attempts to swallow bigger and bigger preys could be a semi-safe, fun way to find out the answer, if the DM is reluctant on giving mechanical details right away - and the druid has off-time to experiment.

RAW - the only interpretation can be taken from the equipment section of the Wildshape description (emphasis mine):

You choose whether your Equipment falls to the ground in your space, merges into your new form, or is worn by it. Worn Equipment functions as normal, but the DM decides whether it is practical for the new form to wear a piece of Equipment, based on the creature's shape and size. Your Equipment doesn't change size or shape to match the new form, and any Equipment that the new form can't wear must either fall to the ground or merge with it. Equipment that merges with the form has no effect until you leave the form.

Albeit, this is referencing equipment that is worn by the druid when shifting into a beast form. So for example, your gnome druid would not be able to keep wearing its leather armour - the toad form is too big to wear it. So it must either be dropped, or merge with the transformation.

This could work the same way in reverse. Upon transforming back into the gnome, the medium creature would either be merged with your PC, or dropped (i.e., regurgitated).

Again, this will probably have to be ruled by your DM.

What happens is called flatus or indigestion

The character ate a large meal without allowing time to digest it as a giant frog. Had they stayed in that form longer, the normal frog digestion would render this problem moot.

But since they switched back to humanoid form too quickly, they are not just "full" but "really full" along the lines of eating three pizzas. Expect a passage of wind anon.

RAW there isn't an answer for this.

I thus recommend the above ruling to fill in the gap that RAW failed to foresee, which was "eating something bigger than your head."

At a time like this, rely on RAF rather than RAW.

I remember this question (or a similar one) popping up in a campaign I was in. I believe our DM said that though it's a DM call, he basically sees it as a logical question.

First, note that a toad swallows its food whole. That said, until it's digested, the meal is still in one huge piece. Also, how long took place between eating and transforming? Third, what kind of medium monster was it?

All in all he viewed that as what would actually happen, given everything in consideration, if your giant toad swallowed a deer, then transformed back to a goblin right away, chances are, his head would explode, but if the toad ate the deer and turned back an hour later, then he'd be more lenient to say it's digesting fine.

What's interesting is if your goblin turned into something able to eat a giant toad, then turned back, he'd have the transformation go off as you barf out the toad, resulting in your goblin looking like living toad poop.