Wild shape creepy mechanic

Hi there, Midgardians!

So yesterday I was DMing a party. One of my players is a Druid, and she asked me the following question:

- Can I use Wild Shape and become a tiny spider, then get inside a monster through its ear or nose, and when I am inside of the monster, undo the Wild Shape transformation and make the creature explode from the inside in the process?

I honestly was shocked. Is that possible? 😂

There are not rules for this. The closest would be the rules for entering another creature's space, or maybe being swallowed. Neither of those situations are very friendly to the player attempting to use them offensively. 

So, it is up to DM discretion. Personally, I would counsel against allowing a practically free auto-kill manoeuvre with no limitations. It's just not a good precedent. 

So how do you deny it would work? Easiest would be to ask why they think it would be the enemy creature's insides which would break, rather than the druid being crushed as they tried to expand. Therefore the magic of wildshape just doesn't work that way. 

If you still want to reward the player for creative thinking, then allow them to use this to trigger a surprise attack: The party is hiding nearby, the druid-spider climbs onto the unsuspecting enemy then bursts to full size right in its face and the rest of the party leaps to join the fight. 

Rules As Written, it’s not permissible, as you can’t “willingly end a move” in another creature’s space. There is possibly some scope for interpretation about whether, if the Druid still had movement available that turn after entering the other creature, they had ended their move, but I would argue they had.

Moving around Other Creatures

During your move, you can pass through the space of an ally, a creature that has the Incapacitatedcondition (see the Rules Glossary), a Tiny creature, or a creature that is two sizes larger or smaller than you.

Another creature’s space is Difficult Terrain for you unless that creature is Tiny or your ally.

You can’t willingly end a move in a space occupied by another creature. If you somehow end a turn in a space with another creature, you have the Pronecondition (see the Rules Glossary) unless you are Tiny or are of a larger size than the other creature.

The quoted text there carves out exceptions for Tiny creatures...

Quote from Athanar90 >>

The quoted text there carves out exceptions for Tiny creatures...

 Doh! How did I miss that bit?! 🤦🏻‍♂️

Anyway, I don’t think i would allow it. Either that, or I’d make it clear that suddenly trying to expand your volume in a tightly restricted space would do as much harm to the Druid as to the monster. 

The 2014 rules used to have rules for Squeezing and various caveats on creatures needing enough space for their new form if enlarging or shape-changing. I can’t find those in the 2024 rules. 

I gave her an Heroic Inspiration for the idea.

Quote from RegentCorreon >>

There are not rules for this. The closest would be the rules for entering another creature's space, or maybe being swallowed. Neither of those situations are very friendly to the player attempting to use them offensively. 

So, it is up to DM discretion. Personally, I would counsel against allowing a practically free auto-kill manoeuvre with no limitations. It's just not a good precedent. 

So how do you deny it would work? Easiest would be to ask why they think it would be the enemy creature's insides which would break, rather than the druid being crushed as they tried to expand. Therefore the magic of wildshape just doesn't work that way. 

If you still want to reward the player for creative thinking, then allow them to use this to trigger a surprise attack: The party is hiding nearby, the druid-spider climbs onto the unsuspecting enemy then bursts to full size right in its face and the rest of the party leaps to join the fight. 

 

Those are really good ideas!