A professor (Arthur Franz) of Dunston College comes into possession of a big fish, 300 million years old, long thought to be extinct. The carcass has been shot through with gamma rays as a preservative. Unknown to anyone, this has altered the fish's plasma so that any living organism that comes into contact with it, either by ingestion or inhalation, reverts to its own primitive forebear. Thus, for instance, Sampson the fraternity's dog laps up some fluid from the fish and becomes a sort of savage wolf. You can tell because when the dog growls he bears his teeth and you can see the canine's canonical canines. Bacteria crystallize like some viruses. A normal dragonfly that lights on the fish grows to immense proportions. And Franz manages unwittingly to cut his hand on the coelocanth's teeth and, later, to smoke some plasma-drenched tobacco in his pipe. (Don't ask.) And after this he becomes, well, not any kind of ancestral hominid but rather an ape-headed hairy monster whose idea of decorum is to smash furniture and tear cops limb from limb during his blackouts. The effects are very real but temporary.<br /><br />Nobody believes his "theory", of course, so to prove it, he deliberately injects himself with the plasma under circumstances that ensure he will be shot and killed by the police. He leaves behind a cute girl friend with a Southern accent (Joanna Moore) and a dozen or so students who are probably happy to get out of his lab periods.<br /><br />It's all pretty silly. The plot is full of holes, for one thing. How is Franz, a professor yet, unable to link his blackouts with the appearance of the ape-monster? The audience can figure it out right off the bat. How does a normal, healthy young woman die of fright? Why is the unit of measurement of evidence always a "shred"? Why are cops told they don't have a shred of evidence. Suppose they did have a shred. Could they then have two shreds of evidence -- or even three? Could they go to trial with half a shred? How about a nanoshred? I kind of like Arthur Franz. Square of jaw and imperturbable, he's the very model of a pedestrian actor. (He was pretty good in "The Sniper," his best picture.) Besides, he must have a great deal of determination to have worked his way out of Perth Amboy, New Jersey, a city in whose legend brick factories loom prominently.<br /><br />Troy Donahue, on the other hand. Well. The best performance comes from Judson Pratt (great as the frequently inebriated Sergeant Kirby in John Ford's "The Horse Soldiers"). He's everything that Donahue is not. He's animated. He has the pushed-in face and big ears of a proletarian. And not just a proletarian but a Boston proletarian, with a regional accent so thick that every vowel should have a German umlaut over it.<br /><br />There's nothing that comes to mind that might have saved this film from it own tedium. I liked the coelocanth, though. It was a real biological find at the time and much in the news. And linking this primitive fish to the appearance of avatars was imaginative, though I don't know what gamma rays could have had to do with it. They're just X rays and they don't preserve anything.<br /><br />All in all, some silly lines in the dialog aside, it's a dull movie.