Idea for a Champion Ability (New Form of CC)

Would be a basic ability.

Seal of Fate: Target a Area of Effect up to 900 units away after a short delay the area is hexed dealing damage to all targets hit and applying 'Sealed' to targets at the epicenter. Damage AOE 125 units, epicenter 50 units, delay, 0.4 seconds.

Sealed: A target that is Sealed is unable to use the last basic ability they used for 10 seconds after the ability comes off cooldown. The icon of the Sealed ability appears next to the targets health-bar indicating to allies and enemies which ability has been sealed along with a duration.

Just thought it was a cool form of CC that has yet to be added to the game. It's basically adding cooldown to an ability last used or if its about to come off cooldown it just add's 10 more seconds or if its off cooldown then it blocks it for 10 seconds. So its a unique form of Silence that is focusing the effect on one ability for a longer duration rather then a spread out silence that blocks all abilities for a shorter duration.