Sorry. I've gotten a lot of disapointing Mud Shot Omastars also.
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Sadly no... he double resists fire, but those are rarely found in gyms, plus you'd be better off with WG/HP against those.
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I've one maxed out at level 34.5 but just for fun. If you don't have too much dust, don't even consider it.
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I used one for the first time ever when prestiging against a flareon. No wait scratch that I used Omanyte actually lol. So my answer is no it is not goid for anything.