Stoneskin

[CapnZapp]

The old old school kind!

Here's my attempt at implementing this. (Currently it's an item effect, but would be easy to stat up as a spell)

Gorgon Plate 13,500 sp
This is a suit of half plate armor +1. It provides a +1 bonus to Strength and Constitution saving throws, resistance to acid damage and immunity to the petrified condition. In addition, you may spend a bonus action to cover your skin in 1d6+4 layers of brittle stone flakes. Each layer grants you immunity to bludgeoning, piercing, and slashing damage but is removed by any attack or other source of damage, even attacks that only hits AC 13. You can't use this property again until you finish a long rest.​

 

[UngeheuerLich]

I loved that stone skin effect.
This way it would be worth the material cost as a spell.
1d6+4 layers of immunity sounds strong enoug that you don´t want to have it all the time.

 

[Cap'n Kobold]

So elemental or similar effects will both do full damage to the recipient and also remove layers of protection?

 

[MarkB]

Drop the "AC 13" part, it's more fiddly than is worth tracking. It's a bit weird having any type of damage strip off a layer - especially psychic damage.

 

[CapnZapp]

Drop the "AC 13" part, it's more fiddly than is worth tracking. It's a bit weird having any type of damage strip off a layer - especially psychic damage.

Actually, what I find weird is that any attack, no matter how inept, could strip off a layer (like in the original AD&D spell).

Hence the AC. Compare to Mirror Image, a spell that asks you to do "fiddly tracking" in precisely the same manner. Except that, for the purposes of items, I simplify AC 10 + Dexterity to 12 (the maximum allowance for medium armor), and then add +1 (it is magic armor after all).

So there is some consideration behind the number!

Thanks for the feedback