Teemo's reign of terror is back in full, thanks to the removal Oracle's Extract from ARAM in patch 10.23. Oracle's Extract granted true sight and obscured vision of hidden enemy units for five minutes. It allowed players to detect Teemo's mushrooms on the map and move around safely.

What can reveal teemo?

Teemo, on the other hand, can stay invisible forever as long as he doesn't move outside of a brush. The only thing that can reveal Invisible champions is true sight, i.e. Control Wards, towers or Scanners.

Does Oracle's lens disable pink wards?

Stealthed traps and wards are revealed. Wards are also disabled.