This is an occasionally satisfying attempt at Quatermass-style science fiction from Hammer Films. The goopy mass that terrorizes throughout the film seems like an inspiration for "The Blob", which will follow a couple of years later. The creeping gob from the center of the Earth doesn't show up until later in the movie, but near the end it slithers around quite a bit, which makes the whole endeavor more fun overall. This has to score some points for originality and for the subdued performance of Dean Jagger as Dr. Royston. There's an overabundance of silly science and clicking Gieger counters, and the disposal of the monster is a yawner. However, there's some slightly suspenseful moments that make the whole thing worth a watch.

Fun early sci-fi from Hammer. Decent effects for the time, and the acting and story is actually pretty great. It has the feel of a Quatermass film, and was apparently meant as a sequel to The Quatermass Xperiment, but ended up as a standalone because of some disagreements about the script. No matter who the egghead is, X the Unknown is a quite fun little film, and I think any fan of sci-fi from back in the day, would enjoy this.