Reduce the casting cost of Energy Twister to 25 Arcane Power.

Energy Twister's damage turns into Cold.

Enemies hit by Energy Twister take 15% increased damage from Fire for 4 seconds.

When two Energy Twisters collide, they merge into a tornado with increased area of effect that causes 3200% weapon damage as Arcane over 6 seconds.

Energy Twister no longer travels but spins in place, dealing 835% weapon damage as Arcane over 6 seconds to everything caught in it.

Each cast of Energy Twister grants you a Lightning Charge. You can store up to 3 Lightning Charges at a time. Casting a Signature spell releases all Lightning Charges as a bolt of Lightning that deals 196% weapon damage as Lightning per Lightning Charge.

Energy Twister's damage turns into Lightning.

The following skills are Signature spells:
Magic Missile
Shock Pulse
Spectral Blade
Electrocute