You're right, that is bagon's (salamence's) hidden ability, but it is not legally obtainable in the DW or anywhere else yet. If u see someone battling with one, it is a hack.
But I will gladly give u slowpoke instead :) Let me check to see if i have one ready to go...
Hi, sorry for taking so long to respond to your post on my Dream World thread! Unfortunately, Bagon is not released yet, but I can give u the other 2 and a different 3rd one if you'd like :)