As two actions, a bolt of lightning arcs toward a target that you can touch or see within 10 meters. The lightning can then arc to another target within 5 meters of the first target and a third target within 5 meters of the second target. A target can be a creature or an object and can be targeted only once. A target must make a Reflex saving throw.
On a failure, it takes 5d8 lightning damage and can’t take reactions until the end of its next turn.
On a critical failure, it takes twice as much damage.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
The lightning can arc to an additional target within 5 meters of the previous target for each additional mana expended and the damage increases by 1d8 for each additional mana expended and by an additional 1d8 for every two additional mana expended. You can end the chain at any point.