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The second BellyBurden set doesn't lose to Blissey. At worst, you'll lose to a Chansey if you somehow haven't chipped it before setting up.
The first set isn't worried about either one with Power Trip.
I made attempts to play Sunday, but my opponent decided to spend their only free time battling someone else, going offline right after. When I went back to his profile, he told me to 'fuck off'.