I think I just found the perfect Boss catcher.
It's a Gardevoir with Draining Kiss and Heal Pulse.
I attack until it gets to low health and then heal it back and try again until it wobbles, and since Draining Kiss heals the user I can just kill some minions to get back to full health.
>>23326933The Donphan goonies suck and the fact Zygarde attacks with pretty large AoE moves it can be.
I got it first try though with the help of my Gutsy Superfang Zubat.
'lil fucker is quick. Perfect for speeding around attacks.