Rain of Rust
You conjure a red raincloud in a 10-foot burst within 60 feet, which pours rust-colored rain directly below it. Any creature in the rain with the metal trait, that is made of metal, or is wearing metal armor is covered in corrosive build-up. Any such creature is Clumsy 1 as long as it remains in the area. If such a creature is in the rain at the start of its turn, it takes (scaling+3)d6 untyped damage with a fortitude save against your class DC, plus 1d6 persistent untyped damage if it fails. Damage from this impulse ignores Hardness. The cloud lasts 1 minute but ends if you use the impulse again.
Level (+2) The initial damage increases by 1d6.
Traits
A composite impulse combines multiple elements. You can gain an impulse with the composite trait only if your kinetic elements include all the elements listed in the impulse's traits.
The primary magical actions kineticists use are called impulses. You can use an impulse only if your kinetic aura is active and channeling that element, and only if you have a hand free to shape the elemental flow. The impulse trait means the action has the concentrate trait unless another ability changes this. If an impulse allows you to choose an element, you can choose any element you're channeling, and the impulse gains that element's trait.
This indicates abilities from the kineticist class.
Effects with the metal trait conjure or manipulate metal. Those that manipulate metal have no effect in an area without metal. Creatures with this trait consist primarily of metal or have a connection to magical metal.
This magic comes from the primal tradition, connecting to the natural world and instinct. Anything with this trait is magical. A creature with this trait is primarily constituted of or has a strong connection to primal magic.
Effects with the water trait either manipulate or conjure water. Those that manipulate water have no effect in an area without water. Creatures with this trait consist primarily of water or have a connection to magical water.