New Summoner Spell Idea: Invisibility

Simply a summoner spell that allows you to go invisible for a few seconds. Pink wards, as always, reveal you. Maybe include a small radius around the champion that uses the invisibility that reveals them if an enemy champion walks within the radius (like Evelynn). I have no clue if light was already shed on this concept in the boards, but let me know what you guys think.

Thank you!