At long last...

http://www.surrenderat20.net/2015/02/217-pbe-update.html

Mandrake Ward

Click to Consume:Places an invisible blind sentry in a brush for 5 minutes. The plant will ping the map if a visible or invisible enemy enemy is within 900 range.

So, Riot finally realized that to have meaningful ways of dealing with useful invisiblity, they needed something that did not tie into vision denial.

buffs incoming?