Whirling Grindstone [two-actions] Feat 4Attack Composite Earth Impulse Kineticist Metal Primal Source Rage of Elements pg. 36
A whirling grindstone made of flint appears in an unoccupied square within 30 feet. The grindstone shreds flesh and shoots sparks. Attempt an impulse attack roll against the AC of a creature adjacent to the grindstone. On a hit, the creature takes 2d6 slashing damage and 1d6 fire damage (or double damage on a critical hit). The grindstone lasts until the end of your next turn, and you can Sustain the impulse up to 1 minute. On subsequent turns, the first time you Sustain the impulse that turn, you can roll the grindstone up to 20 feet and can repeat the attack.
A creature within reach of the grindstone can Interact with it to sharpen a metal weapon. This grants a +2 circumstance bonus to the next damage roll made with that weapon within 1 minute.
Level (+5) The grindstone's damage increases by 1d6 slashing and 1d6 fire, and the bonus to weapons increases by 1.
Traits
Attack: An ability with this trait involves an attack. For each attack you make beyond the first on your turn, you take a multiple attack penalty.
Composite: 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.
Earth: 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 magical connection to that element. Planes with this trait are mostly solid, with caverns and other hollow pockets.
Impulse: 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.
Metal: 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.
These planes consist of chaotic and shifting structures and oceans of metal. Metal planes tend to exist in a state of change and decay, leaving plentiful pockets of air for visitors to breathe or move within. Creatures unlucky enough to be entombed in the plane’s substance risk suffocation if they can’t phase through metal. Wood creatures find the lack of stability and soil on a metal plane disconcerting and often fail to thrive in such environments.
Primal: This magic comes from the primal tradition, connecting to the natural world and instinct. Anything with this trait is magical.