The Hideous Sun Demon - 1958
The Hideous Sun Demon - 1958 - Low budget monster effort starring Robert Clarke. He is a tormented nuclear scientist who discovers after a lab accident involving isotopes that he alters into a violent lizard-man when exposed to sun light. Needless to say, this is problematic for he and his would-be girlfriend (Patricia Manning). Consequently, a good portion of this tale takes place at a night, conveniently at a night club where the scientist watches a pretty lounge singer (played by Nan Peterson) and the pair take off to swim and sleep overnight at the local beach, which turns into a disaster when the sun comes up.
Star Robert Clarke also directed this film and he keeps it moving as the lizard-man/scientist struggles to keep his sanity and to defeat the gangster boyfriend who keeps a proprietary eye on the lounge singer.
While The Hideous Sun Demon seems to mimic the usual 1950s science-gone-wrong films that had come before, it also throws in a piece of King Kong for a poetic finis, and contains a certain energetic get-up-and-go that helps compensate for the thin budget.
Page December 2018

Into the Dark - The Hidden World of Film Noir 1941-1950 -amazon.com
Universal Horrors: The Studio's Classic Films, 1931-1946, 2d ed.