thingservant (n.):

The changeling you keep on staff to turn into whatever inanimate object you need that you put down somewhere obvious, now can't find, and swear was there just a moment ago.

(Most households have to replace changelings in the role of thingservant every couple of years, since a steady diet of intermittent bursts of intense gratitude and relief tends to cause the formation of fatty plaques in, and eventual calcification of, the splanch.)