The Mutated Creature was a creature created due to the Interdimensional parasite entering the body of another animal. The parasite releases radiation that transforms the animal into a giant monster.
On P9J-333 in 2006, the parasite invaded the body of a Travora and was killed by Vala Mal Doran and Teal'c.
On Earth in that year, two creatures were created by unknown animals and killed by SG-1, Major General Henry Landry and Colonel Albert Reynolds. It was speculated that the host animal was likely a grizzly bear. (SG1: "Uninvited")