It moves swiftly from a radioactive volcano to a Mayan grotto for an irresistible picture of the jungles of Tikal by way of a Roman studio. ("Based on an ancient Mexican legend," pledge the credits.) The archeologists’ camp at night is lit with torches and an eye for the Everglades picnic sequence in Citizen Kane, the underwater views of skeletons set up the startling shot of a diver pulled out with his skull half-dissolved, the first victim of the eponymous creature. Back in Mexico City, the spelunker whose arm was nearly melted off (Gérard Heller) mutates into a raving killer, while Caltiki takes advantage of the sudden appearance of a comet to dilate from a prehistoric sponge into a humongous, marauding bowl of pudding. "This case has no precedence in the history of medicine," a doctor calmly tells the square-jawed hero (John Merivale). Riccardo Freda reportedly walked off the project early on so that his assistant could show off his gifts, and indeed Mario Bava’s signature is obvious as soon as the camera pans over the placid surface of a lagoon to reveal a corpse grinning at the camera. (His zoom makes its debut appearance some scenes later.) Quite a delectable vision of viscous mayhem, building on Yeaworth’s The Blob and Guest’s The Quatermass Xperiment to arrive at a gated garden overrun by flamethrowers and tanks, a dense surrealism surely appreciated by Chano Urueta (El Barón del Terror). With Didi Perego, Daniela Rocca, Daniele Vargas, and Giacomo Rossi-Stuart. In black and white.
--- Fernando F. Croce