Galarian Runerigus CRE 83

If this Pokémon is in the Active Spot and is damaged by an attack from your opponent's Pokémon VMAX (even if this Pokémon is Knocked Out), put damage counters on the Attacking Pokémon equal to the damage done to this Pokémon.

This attack does 20 more damage for each Energy attached to your opponent's Active Pokémon.