[Phantasm]

You have a few options:

Crushing Attack w/ Melee Attack: Reach C and Armor Divisor;

Modified ST-Based Damage (accounting for the bonus from Striking ST) with Armor Divisor added to it; or

Imbue (possibly with a Chi power modifier) + Penetrating Blow.

Tack a Melee-Based Damage modifier onto the Crushing Attack, and you can add the first two options together. Remove the Armor Divisor from the Crushing Attack, and you can possibly end up combining all three.