Horsehead Nebula

The Horsehead Nebula was a nebula located within the galaxy of Mutter's Spiral.

Locations
The Ood Sphere, homeworld of the Ood, was located here. (DWA: Doctor Who The Official Annual 2007) The Tenth Doctor stated that the Ood Sphere and the Sense Sphere were in the same star system, which would make the Sensorites also native to the Horsehead Nebula. (DW: Planet of the Ood)

The planet Dramos was located in the Horsehead Nebula. (BNA: The Mary-Sue Extrusion)

Events
During the Millennium War, the Mad Mind of Bophemeral attempted to create a wormhole in the Horsehead Nebula which would have killed quintillions had his plan not been stopped by the Osirians. (PDA: The Quantum Archangel)

The Uvodni and the Malakh fought the Ghost Wars against each other within the Nebula. (SJA: Warriors of Kudlak)

In 2006, a plasma storm was occurring in the Horsehead Nebula. The Ninth Doctor planned to ride it with the TARDIS and invited Rose to come along. (DW: World War Three)

The Tenth Doctor took Grayla to either the Horsehead Nebula or the Crab Nebula. (IDW: The Whispering Gallery)