Their actions, though harmless, horrified me even more than their appearance - for it is not wholesome to watch monstrous objects doing what one had known only human beings to do. These objects moved intelligently about the great rooms, getting books from the shelves and taking them to the great tables, or vice versa, and sometimes writing diligently with a peculiar rod gripped in the greenish head tentacles. The huge nippers were used in carrying books and in conversation-speech consisting of a kind of clicking and scraping. - H.P. Lovecraft, "The Shadow Out of Time"
The "Great Race" of Yith explore the universe by swapping minds with other creatures existing in the future. The Yithian visits the future world inside the (unwilling) donor's body, while the donor's mind resides safely in the Yithian's body, a billion years in Earth's past. They are free to explore and travel there, but their memories of Yith are largely erased before their eventual return to their own time. The Yithians are locked in perpetual war with the Flying Polyps, eventually leading to the destruction of their civilization.