I ended up laning against a Xerath bot and he was only casting his stun. He would charge his Q but no cast it, I never saw him cast his AoE, His ult would simply root him and show the range but he would never cast.
--Play a Bot game on Summoners Rift (alternatively you can do custom game and set Xerath as an opponent)
--Choose any Champ
--Magically get Xerath as an opponent and get hella easy kills