I used all the items they allowed in 1 battle more than 6 times, and I used Mega Charizard Y as much as I can, but I still never beat Spewpa!
Yeah, just listen to the comments. You just put Scatterbug in your team. It made like a 30 combo right after I began the battle, with all my moves remaining. Didn't use a single move and I smashed it outta the park.