“Dr. Gavin, can they be killed?” “I don’t know Lieutenant.”

Not far from a beach filled with teenagers a boat dumps a 55-gallon drum of radioactive waste into the ocean. The drum opens and the liquid inside spreads over a skeleton that happens to be on a sunken ship. The waste transforms the skeleton into an aquatic humanoid monster. The monster swims to a nearby jetty and kills a girl, Tina (Marilyn Clarke), that was sitting by the water. The girl’s boyfriend was Hank Green (John Scott). He works for Dr. Gavin (Allan Laurel).

The police ask Dr. Gavin if he can assist in finding out what caused the girl's death. They have a tissue sample they want him to look at. Dr. Gavin’s daughter Elaine (Alice Lyon) is a friend of Hank and has feelings for him. She is feeling bad about Tina’s death and decides not to go to a slumber party that she had been invited to.

The girls at the slumber party are having a good time until a bunch of sea monsters come out of the water and attack them. They kill a bunch of the girls and kidnap others. In another incident three girls driving through town get a flat tire. They get attacked by the monsters. Then two women walking through town are stalked by a sea monster. When they are picked up by a car the monster gets mad and attacks female mannequins in a storefront window. In the process it breaks a plate glass window and loses an arm.

Dr. Gavin and Hank study the arm which is still alive. Dr. Gavin calls the creature a sea anemone. A species of protozoa. Or some such nonsense. The scientific stuff is lame. They are trying to figure out a way to kill the monsters when Dr. Gavin’s housekeeper, Eulabelle (Eulabelle Moore) accidentally spills liquid metallic sodium on it and it bursts into flame and dies. Now all Dr. Gavin needs is to formulate a plan and enough metallic sodium to kill all the monsters. In the meantime the monsters continue their rampage across the land.

“The Horror of Party Beach” was released in 1964 and was directed by Del Tenney. The party music was performed by The Del-Aires musical group. They were a New Jersey band. The rest of the music is pretty much canned. The movie also has the lamest jokes I’ve ever heard. For example; “Do you like bathing beauties?” “I don’t know I’ve never bathed one.” The monsters are also dumb, but that’s to be expected. According to the director they only had two monster heads. For some reason there seems to be two different types of monster. At lease they look different. On the other hand, the transformation sequence of them turning from skeletons to fish people is actually eerie.

A promotional sign posted outside each theater stated: "FOR YOUR PROTECTION! We will not permit you to see these shockers unless you agree to release the theatre of all responsibility for death by fright!". Moviegoers actually had to sign a "Fright Release" before they entered the theater.

I may be wrong but, to me, the whole movie is shades of “Humanoids from the Deep” 1980 by Roger Corman. The story says that the monsters live off human blood, but the monsters attack and kidnap mostly women. Although the movie doesn’t say anything about them breeding with women, it seems logical to me since it is women they attack and women that they take into the water with them. There are only three guys that get attacked. Unless it’s a sexist thing instead of a sexual thing. But I doubt it.