You exhale corrosive gas, and acidic secretions coat your skin as you transform into a being of living acid. You gain acid immunity. Any creature that touches you or damages you with an unarmed melee attack or non-reach melee weapon takes 3d6 acid damage, and your unarmed attacks deal 1d4 additional acid damage. The first time each round that you deal acid damage to a creature in this way, you gain 3d6 Temporary Hit Points temporary Hit Points as your body digests the eroded material and transforms it into a protective acid. When the spell ends, any remaining temporary HP expires as well. Your acid spells deal one additional die of acid damage (of the same damage die the spell uses). You can cast Acid Splash as an innate spell; the splash damage affects all creatures within 15 feet instead of the normal 5 feet.
Spell Effect: Corrosive Body
Heightened (9th) Creatures touching you take 4d6 acid damage instead of 3d6, your unarmed attacks deal 2d4 additional acid damage, and you gain 5d6 Temporary Hit Points temporary Hit Points.
Traits
Effects with this trait deal acid damage. Creatures with this trait have a magical connection to acid.
An action with this trait requires a degree of mental concentration and discipline.
You must physically manipulate an item or make gestures to use an action with this trait. Creatures without a suitable appendage can't perform actions with this trait. Manipulate actions often trigger reactions.
These effects completely transform the target into a new form. A target can't be under the effect of more than one polymorph at a time. If it comes under the effect of another, the second effect attempts to counteract the first. If it succeeds, it takes effect, and if it fails, the spell has no effect on that target. Any Strikes granted by a polymorph effect are magical. Unless otherwise stated, polymorph spells don't allow the target to take on the appearance of a specific individual creature. If you take on a battle form with a polymorph spell, the special statistics can be adjusted only by circumstance bonuses, status bonuses, and penalties. Unless otherwise noted, the battle form prevents you from casting spells, speaking, and using most manipulate actions that require hands. (If there's doubt about whether you can use an action, the GM decides.) Your gear is absorbed into you; the constant abilities of your gear still function, but you can't activate any items. You lose your Speeds and gain those of the battle form. If a polymorph effect causes you to increase in size, you must have space to expand into or the effect is disrupted.