Night Fright

Night Fright is a 1967 American science-fiction horror film directed by James A. Sullivan that was shot near Dallas, Texas.
In the early 1980s, the film was re-titled in the United Kingdom for VHS release as E.T.N.: The Extraterrestrial Nastie, E.T.N.: The Extraterrestrial Nasty, The Extraterrestrial Nastie and The Extraterrestrial Nasty .
Plot summary.
A Texas community is beset by a rash of mysterious killings involving some of the students from the local college. The sheriff investigating the deaths discovers the startling identity of the killer responsible for the murders. A NASA experiment involving cosmic rays has mutated an alligator into an ogre-like form and bullet-proof unstoppable killing machine with a thirst for blood.
Soundtrack.
The soundtrack was performed by the Houston, Texas garage band The Wildcats. The band also played in another movie scored by Christopher Trussell also filmed in 1967 entitled "Fulfillment: Something Worth Remembering".