There are many hundreds of documented claims of abductions, namely instances when the witness of a close encounter has recalled under hypnosis about being forcibly taken inside a UFO. The witnesses generally describe being subject to medical examination (often causing trauma and pain). These claims are substantiated by scars on the body and missing time in their conscious recollections during that period.
The encounters remembered by witnesses, if they occurred at all, should be treated at the symbolic level. They do not provide information about the extraterrestrial origin of the beings. To the extent that there is underlying reality to the UFO phenomenon, they provide a physical support for human ability to use them as symbols in response to inner needs.