Sweet merciful Batman, you people argue about the most POINTLESS crap! I mean, who even GIVES a **** whether Yamask using Shadow Ball makes the episode filler?! Me? I'm waiting on what Seger said before dismissing this as a filler, just because this could potentially mean it's not.
EDIT: Bulbapedia at the very least seems to consider Yamask knowing Shadow Ball a major event. Not saying it is, but again, waiting on Seger's words.
Pokemon Y Friend Code: 3282-3535-2249
Friend Safari: Pansage, Petilil, Gogoat
As of now, my focus is on Safaris with starters (barring Wartortle and Quilladin), but give me your Safari anyway. Chances are I'll find something interesting.