Sion ult bug/hack

I just played a TT game against a sion. He was able to ult from jungle up to vilemaw to try to see if I was there, I was at my turret. He them proceded to somehow maneuver through the vilemaw camp and make a semi circle around my turret while I tried to dodge him.

Then next time his ult came up, He ulted from base while I was attacking his turret. I ran down underneath the island below his turret and he looped around past his turret making a 180 and hit me.

Basically it had complete control of his champ, except with the sion speed boost. His name was CHOCOLATE POOOOO