"Nasty creature" was a native predator on the planet Novus. It is unknown what the creature looked like.
After the alternative Destiny expedition had have abandoned Destiny in hopes of returning to Earth, but after they arrived to the planet and settled there they found them, predator and began to run out of bullets by defending themselves against the local predator. The predator died out long after the People of Novus had abandon their homeplanet Novus. (SGU: "Epilogue")