Here's a monster movie that truly belongs in the POS file. Sometimes even top-bill actors and actresses sometimes get rooked into doing POS movies (prime example: Halle Barry and 'Cat Woman') and for 'Monstroid', it was James Mitchum and John Carradine. The director, Kenneth Hartford, starred his own kids in the movie and gave them top billing with Mitchum and Carradine to add insult to injury.
This steaming pile of doo-doo is about a big, bad American company operating a chemical plant in Colombia. The plant has been dumping untreated chemical waste into the local lake for years and of course the company execs don't care. The chemical waste has somehow spawned a rubber monster to appear from its depths, whereupon it begins chomping down on bikini-clad harlots and drunken fishermen. The company execs devise a hare-brained plan to kill the creature with a lamb carcass stuffed full of dynamite pulled along by a helicopter. No, really... I kid you not...
This is a really awful film. It is tedious and ridiculous. The file I saw was pulled off of the public domain films section of http://www.archive.org so the quality was quite poor. Even if I could have seen the master copy, however, I'm sure the film would have sucked just as bad. Most likely, John Carradine and James Mitchum cashed their checks and got falling-down drunk after this POS finally wrapped.