They come from the Frozen Stomach which you find in the glaciers if Volster.
Cryobian Ice/Water: a once very common Pokemon that seems to have been a favored prey for many aquatic predators. Now we usually find their remains in the stomach of larger Pokemon.
Glacior Ice/Water: an Apex predator of swamps. In the past it most likely had a different pre evolution and type but due to only ever finding its stomach remains frozen filled with Cryobian their DNA mixed through the reviving process, turning them ibto obe evolution line in modern day.
by Delicious-Pop-9063