Spike Skin
You touch a willing creature, causing its skin to harden and form spiky protrusions. The target gains resistance 4 to all physical damage (except adamantine).
Effect: Spike Skin
Whenever a creature damages the target with an unarmed attack or non-reach melee weapon, the attacking creature takes scaling piercing damage.
This impulse lasts for 10 minutes, but each time the target takes physical damage, the duration decreases by 1 minute. The target is temporarily immune to this impulse for 1 hour. If you use Spike Skin again, any previous one ends.
Level (+2) The resistance and damage each increase by 2.
Traits
Effects with the earth trait either manipulate or conjure earth. Those that manipulate earth have no effect in an area without earth. Creatures with this trait consist primarily of earth or have a connection to magical earth.
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.
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.