With only a few boosts, Kyurem can switch out for a fighting type and with a lot of boosts, Cloyster is wrecked by Dragon Tail. That's why I said Focus Sash, though in hindsight, White Herb would work too. But I'm serious about Suction Cups Craydily. It seems like a surefire counter to Kyurem-B. I'll post a set soon, but with Curse, Rock Slide, Rest, and Sleep Talk (or Curse, Recover, Earthquake and Rock Slide), Kyrem becomes set-up fodder for Craydily. Dragon Tail can't force it out as it stacks boosts then rests off all damage.