A Close Encounter of the second kind is a close encounter of a UFO event in which a physical effect is alleged. This can be interference in the functioning of a vehicle or electronic device; animals reacting; a physiological effect such as paralysis or heat and discomfort in the witness; or some physical trace like impressions in the ground, scorched or otherwise affected vegetation, or a chemical trace.
- ↑ J. Allen Hynek, The UFO Experience: A Scientific Enquiry, Ballantine Books, 1972, pp. 98-9.
Informania: Aliens, page 18