concentration, 1 minute/mana

As two actions, you expose a creature that you can touch or see within 10 meters to poison. The creature must make a Fortitude saving throw.

On a failure, it loses any resistance to poison damage for the duration and the first time on each turn the creature takes poison damage, it takes an extra 2d6 poison damage.

Augment

You can target two additional creatures for each additional mana expended. The creatures must be within 5 meters of each other when you target them.