Sketch is like a move called metronome or mimic. It can learn any move personally. Heres a hint! To get a great, stunning move, enter a double battle with a superior pokemon and Smeargle. Have your great pokemon use the move it wants smeargle to use and use sketch on your pokemon and have it learn that move. Honestly, it's better then battling a wild pokemon that uses growl and now you don't have a effective move. Anyway, hopes this helps! :D