The Half-dead city

[Sadbackstory.exe]

So this is my first time as a DM, and I would like some help on a creative matter regarding the False Sarcophagus. I'm a librarian at a high school and me and a teacher are running this game. As we left off in our game a student in my group, a Psychic Aquatic Elf, just got swallowed by the Sarcophagus after opening it.
She came up to me today wanting to tell me her plan that shes very excited about. So she can summon a 5x5 cube of water. She was talking with her dad on the way home and apparently they thought that maybe after enough turns of summoning this water that it would create a lot of pressure inside the Sarcophagus and burst it open, expelling her and damaging/destroying it.
I want to have this work in some fashion, but I'm not 100% sure on how to do it. I thought that I could perhaps have the Sarcophagus and her both take damage (because shes being crushed by the water too technically) but then I realized that she might not take it since shes an aquatic elf and that their bodies might be used to pressure.
Anyways, I'm just wondering if any of you more experienced DMs have any suggestions on how to deal with this crazy idea.

[Andre Roy]

It's a creative plan, and I'm all for rewarding creativity...or at least give it a fighting chance of success.

Unless very big, the first casting (125 square feet of water) should pretty much fill up the occupied sarcophagus (Assuming 4x4x10 dimension for 160 square feet)...the last 35 square feet being mostly occupied by the elf. If the air cannot "leak out" of the sarcophagus, that will already cause a lot of pressure that could potentially pop it open say a DC 20 Con, Fort or Hardness check for the false sarcophagus

The 2nd casting would fill up the remaining space either creating more pressure (say adding a +10 to the DC) or leak out from the mouth/seal (either unchanged or a +2 to +5 to the DC check depending on how much and how fast it leaks).

Every subsequent casting would increase the DC at the same rate as the 2nd. Starting on the 3rd casting or 4th casting the elf should start making a similar roll (starting at DC 20) as IIRC Aquatic elf doesn't go that deep after all (based on Cerulean Seas and the old 2nd edition underwater material).

[Sadbackstory.exe]

Awesome! Thanks for the advice, that sounds perfect!

[Andre Roy]

This idea reminded me of something I read about a while back, a torture technique where huge quantities of liquid were poured in a funnel directly into the poor soul's stomach, several bottles in quick succession in fact. Causing massing swelling of the stomach, unbearable pain, possible rupture of the stomach and very messy "evacuation" from both end.

So I'm seeing something along those line here thus the Check ideas for the sarcophagus.

[Sadbackstory.exe]

Thanks, I love it!

Problem is, she'll never make that con roll. This is lvl 1, and she has 6 con (she didnt roll all that well).

I was thinking that I'll say that the second cube of water will start making things uncomfortable for her, and the 3rd I'll roll 1d4 for bludgeoning damage. She only has 4hp so hopefully I dont roll high haha

[Roonfizzle Garnackle]

I did some googling, and while it's 5th ed AND house rules, it might give a place to stand and make adjustments for your situation.

5th ed underwater charts!

Depth CON Save Points of Damage
0-200 ft none none
201-250 ft DC 10 1d6/minute
251-300 ft DC 15 2d6/minute
301-400 ft DC 20 3d6/minute
401-500 ft DC 25 4d6/minute
501-1000 ft DC 30 5d6/minute
1001 ft or deeper DC 35 6d6/minute

An idea, given that she's 1st level, would be to use nonlethal damage for the first cube that you do damage with?

More Googling, found me a 3.5 to 5e conversion guide, with the following for For natural attacks by medium or larger creatures, use the following table:
.

3.5 Damage Dice - 5E Damage Dice
1d4 - 1d6 (or 2d4)
1d6 - 1d8 (or 2d6)
1d8 - 1d10 (or 2d8)
1d10 - 1d12 (or 2d10)
1d12 - 2d8 (or 2d12)

So, going in reverse, looks like 1d4 / minute seems reasonable for ~200' equivalence of pressure. After of course, you determine what depth her race gives for free. Saving throw DC's appear to be lower in 5th ed, but ... she's 1st level.

Hopefully that's enough to give you more to work with and make a ruling during next game.

[Sadbackstory.exe]

Non-lethal! That will work! Awesome, now I wont feel so bad if she goes down haha

[Andre Roy]

Non-lethal would work yes.

But to be fair (and just in case), the sarcophagus is the only one doing a Check for the first 2 or 3 rounds only thdn would the pressure be too much for the elf.

So unless the sarcophagus roll well, she should be out before having to do any roll.