Ordinary objects rendered issuable

I've always been unsettled when ordinary, household objects are made sinister, like Man Ray's Cadeau, or Meret Oppenheim's Object.  The first time I saw an image in an art history textbook of the surrealistic iron with a row of spikes down the middle, I had this intense, visceral reaction of repulsion and unease - it was one of the first times I remember being completely unsettled by an work of art. That was only from a picture, so I can't even imagine what seeing it in person (and physically sharing space with a such a threatening object) would be like.