Man, Zygarde's 50% Forme is an interesting stage, for sure! With the possibility to "anger" him on a timer (and possibly jump past harder stages later on), I assume by making a match when his icons pop up! Not always though, in at least one case when he wasn't already "angry". Took me 8 tries, but I caught him! Though I wish his given Ability was a better one (ie: one like Dancing Dragons)!