At 2204 lbs (999.7 kg), Primal Groudon is the heaviest Pokemon to date.
Which is funny because Mudsdale is 2028.3 lbs (920 kg), which is a normal weight for a real life Clydesdale.
Does GF even think about how height and weight would work? Some Pokemon seem much shorter/taller than they typically would be, and some Pokemon are way too light or way too heavy. Wailord is less dense than air! Yeah, it's Pokemon category is the "Float Whale" Pokemon, but still.