Triangulum Galaxy
Measurements with the Hubble Space Telescope, announced in 2006, suggest the Magellanic Clouds may be moving too fast to be long term companions of the Milky Way. If they are in orbit, that orbit takes at least 4 billion years. They are possibly on a first approach and we are witnessing the start of a galactic merger that may overlap with the Milky Way's expected merger with the Andromeda Galaxy (and perhaps the Triangulum Galaxy) in the future.