Pokémon - That creature... is not Groudon...

SO its essentially a cheap knock off?

"Due to it being created through Jirachi via Butler's selfish wishes, this Groudon-like being was a manifestation of pure evil, and it consumed people and Pokémon alike while sucking up energy from the earth."

This is the most I could find out about it.
Pretty much, it was like this due to being wished for selfishly.

A similar creature was created like this in the Pokemon Adventures manga, but was based off of Kyogre.