Fenri

From SGCommand

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 and appear to be their way of transport to the Nox City . 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. While under the command of Apophis, Teal'c was once ordered to capture a Fenri but failed to do so and lost two Jaffa in the process. Later while Teal'c was apart of SG-1 Apophis himself came to the planet in an attempt to capture a Fenri and figure out how they became invisible. (SG1: "The Nox")