Fiend Without a Face (1958)

 Fiend Without a Face (1958)

A Scientist, experimenting with telekinetic powers enhanced by a 

nearby nuclear power plant succeeds in creating a new form of life. 

This new creature grows in intelligence until it finally escapes 

his laboratory. Once outside the lab, and closer to its nuclear 

power source it multiplies. The creature is also invisible... 

(IMDB harold.lind)