The first film produced by Roger Corman, directed by Wyott Ordung and written by Bill Danch, making it a notable entry in cult cinema history. It was like remade as Sharktopus. Corman is all about being green.

Julie Blair (Anne Kimbell), an American artist on vacation in Mexico, meets marine biologist Steve Dunning (Stuart Wade), who dismisses the sea monster until she provides a tissue sample from an oceanic amoeba, prompting him to attack it in his submarine. 

In fact, that sub was a real one and used for free. That’s why the credit Submarine built by Aerojet General shows up.

There’s a moment in this where the scientists talk about pterodactylus, and Steve says he found an actual egg at one point. This is glossed over, and you may react as I did: Why are we here looking for an amoeba when there are actual dinosaurs alive and in the world?

You can watch this on Tubi.