Pricklypear

yo, yeah my dude. i figured it out a while ago, just forgot to take this down. sorry for the inconvenience.

I currently have defeated Lt. Surge and have many more than 10 different pokemon, yet i still cannot, for the life of me, get flash from him. I have no idea what i have done or am doing wrong but help would be very much appreciated. (also i can not continue without this and the help chat was not very helpful)