Fenri

Fenri are a large, flying species indigenous creatures from the Nox homeworld. They appear to be hostile but mostly keep to themselves and do not harm the Nox. The Nox have been known to conceal the fenri from attack by invaders who arrive through the Stargate and thus have caused many to believe it is the creatures that are capable of disappearing at will. At one point Apophis of the Goa'uld came to the planet in an attempt to capture a Fenri and figure out how they became invisible.