Jubul

Maybe it's random but in the post game quest for xerneas mable asks you to catch or KO anomalous alphas, one of mine was a steelix.

Also for anyone who doesn't know if you set up an online trade with the long code being the dex number (ie 0167-0167 for Scyther/Scizor) you will find a trade in seconds with someone looking for the same thing