Stormsurge

Unique – Stormraider: Dealing damage to an enemy champion equal to 25% of their maximum health within 2.5 seconds inflicts them with Squall and grants you 25% bonus movement speed for 1.5 seconds (30 (starts on application) second cooldown).

Unique – Squall: After 2 seconds of having applied Squall, strike the target with lightning, dealing 125 (+ 10% AP) magic damage to them. If the target dies before being struck, they emit an electric field instantly that shocks all enemy champions near them, dealing them the same damage and granting you 30.

Limited to 1 Stormsurge.