River Song's spacesuit

A spacesuit was the instrument used by the Kovarian Chapter of the Silence to bring about what appeared to be the Eleventh Doctor's death on 22 April, 2011. Capable of operating on its own, it was worn by River Song, who was forced by the Silence into murdering the Doctor as was recorded in history.

History
When the Silence needed space suits, they implanted the idea of travelling to the Moon in the minds of the humans. They then trapped Melody Pond in a modified suit that they'd stolen from the space program; it served as an exoskeleton for her. They put twenty different kinds of alien technology in it, and the space suit was capable of operating without its inhabitant. When the Eleventh Doctor, River Song, Amy Pond and Rory Williams arrived, Melody escaped from the bonds of the suit, destroying it in the process. The suit processed sunlight directly, had built-in weaponry, and a communications system that could hack into anything, including the telephone network. River Song even claimed that you didn't have to eat with it on. (TV: Day of the Moon)

River was again abducted by the Silence and placed in another space suit. She sat submerged in the waters of Lake Silencio, before rising out of it and "killing" the Doctor. (TV: Closing Time, The Wedding of River Song)