League of Legends Reforged Rune: Lethal Tempo

Damaging an enemy champion begins a 1.5 second timer. Upon completion, you gain 40-110% (based on level) attack speed for 3 seconds. Attacking a champion while the effect is active will extend the duration to 6 seconds.

Cooldown: 6 seconds

Lethal Tempo allows you to temporarily exceed the attack speed limit.