Energy Vulnerability (Greater)

A weapon etched with this rune has a sheen of a color corresponding to the energy type chosen when the rune is created: green (acid), blue (cold), white (electricity), orange (fire), or yellow (sonic). When you critically hit a target with a weapon with this rune, the target gains weakness 10 to the chosen energy type until the end of your next turn. This weakness isn't cumulative with any weakness to that energy type the target already has and doesn't affect a creature with immunity or resistance to that energy type.