Admirable film.

Fun premise, good actors, bad writing. This film seemed to have potential at the beginning but it quickly devolves into a trite action film. Ultimately it's very boring.

The acting in this movie is really good.

It is neither dumb nor smart enough to be fun, and spends way too much time with its boring human characters.

This takes place in the Salton Sea in California. There are radioactive slugs in the sea and they begin to feast on the population. They are rubbery things that are created on a low budget. Radioactivity was a constant during this time, especially after the bomb in 1945. I've always had a problem with monster from the sea attacking those on land. There was that giant octopus that went after San Francisco. Its tentacles flopped down on land, but all people really should have done was to walk a few feet away. These things remind one of some sort of insect but they are more like rubber discs. This movie is not up to some of its 1950's peers.

Yep back in the 50's (or more specifically 1957 it seems) they made horror chillers using every kind of bug they could think of, not even the simple mollusk was able to avoid this fate. Yes a sea snail or sea slug I suppose, only these were of course giant prehistoric versions released by yet another pesky earthquake. To note, the films title is again ridiculous as the monster in question isn't actually a monster, its a mollusk as pointed out in the film, and it didn't challenge the world. The films alternative titles were also kinda dumb, 'The Kraken' which is surely an entirely different mythological beast and 'The Jagged Edge'? eh?So anyway, do I detect a slight pattern in plots here? no no no no no...well yes, apparently so. As I already mentioned the sea beasties are released from their watery tombs by another earthquake, the beginning of all monster movies back then. Various military types are killed which triggers a big investigation...by the military...again. Yep the good old US of A just loved their military back then, every monster that emerged from a crack caused by an earthquake, was dealt with by the military...after it attacks the military. Suffice to say this leads to the usual crack team of smartly dressed, slick haired chaps, a scientist type (this time a youngish one) and the obligatory attractive woman (this time with a young female child). Guess what follows?I gotta be honest with this one, I found it pretty dull. For the most part this movie is purely dialog with little else happening. The cast go from room to room discussing stuff, from location to location looking at stuff, explaining scenarios to each other, lots of driving around and of course the other obligatory scene where everyone watches an old educational news film reel about their enemy and how it lives. In this case, the life of a snail and how it feeds.On the other hand this is also one of the most atmospheric of the giant bug movies I've seen, along with 'The Black Scorpion'. This movie genuinely had some really solid creepy sequences, when they actually turned up, mainly underwater and the finale. The underwater sequences actually reminded me of Spielberg's 'Jaws' with very similar shots and ideas in general. The way we follow the divers around almost as if it was from the creatures perspective, the fact we actually see dead bodies with minor jump scares, and the way a female gets dragged under the waves. I can well see this movie really terrifying people back in the day for sure, especially when they uncover shrivelled up, skinless bodies exposing muscle and bulging eyes. Another really well directed scene is the finale where we the towering mollusk in a laboratory attacking the female lead. This sequence kinda reminded me of Cronenberg's 'The Fly' at the end, the creatures posture, the eyes, the claws the camera angles etc...All this leads me to the creature itself, a simple yet large mechanical puppet. Now although this thing just looked like a giant slug, it did look very intimidating with its height and huge pincers. The two big round glaring eyes are also very unnerving and eerie, they gave off no emotion, just a cold blank stare, a pure carnivorous predator with one function. The slimy skin texture really boosted the creatures realistic appearance, you can't really see clearly but the black and white film does admittedly help cover any obvious rubber and seams. Overall its a terrific creature and very lifelike, accept for the exaggerated face I suppose, it didn't move much of course but the large puppet interacted very well with the actors.Its just a shame that we don't really see too much of the giant mollusk, though what we do get is pretty epic and classic I reckon, definitely one of the top Hollywood creatures. You could say that they were hiding the beast as much as possible, building up the tension for the finale, but that theory doesn't really add up. On top of that the rest of the movie is pretty uninteresting frankly, things only become fun and engaging when the creature pops up. All the discussions between characters is a really limp affair and you couldn't really care a less.5.5/10

This story takes place in California - on, under, and near the Salton Sea. One day an earthquake unleashes a particularly hideous brand of giant monster on the locals - massive mollusks. Our heroes include such people as Lieutenant Commander Twillinger (Tim Holt) and the scientist Dr. Jess Rogers (Hans Conreid).All in all, "The Monster That Challenged the World" is an intelligently done, sometimes suspenseful example of this particular genre that blossomed in the 1950s. The thing is, it might not appeal that strongly to all members of the modern audience because there's just not a lot of good monster mollusk action. The runtime is mostly devoted to the efforts of our determined human cast to solve the problem. There's a fair bit of exposition to digest, and there's also a romance that begins to develop between Twillinger and a receptionist named Gail (the very pretty Audrey Dalton).This is still worthy of a viewing from fans of these films. The special effects are pretty good for the era; the creatures are formidable when engaged in battle. People who've seen this are likely to remember that fun grossout moment when one of the mollusks loses its left eye while fighting with some people. This also benefits strongly from some crisp black & white photography by Lester White and a decent music score composed by Heinz Roemheld. The cast is effective all the way down the line. Holt is a likable hero, and Conreid has a valuable presence because he makes the exposition worth a listen. Max Showalter, Harlan Warde, Gordon Jones, and Jody McCrea co-star. That's director Arnold Lavens' wife playing Sally. One cast member in particular is worth mentioning: Milton Parsons as the rather eccentric, helpful Lewis Clark Dodds. He makes the most out of a small role.The finale is reasonably exciting, and Laven and company wrap things up quickly once it's over.Seven out of 10.

"Atmosphere" is probably one of the most important ways to make a movie exciting.Here, we have a science fiction film about giant mollusks in the Salton Sea.Never mind the poor Science. We can call any Science Fiction "poor Science." That's why it's "cience Fiction".We have somewhat likable and believable characters, as opposed to the one dimensional caricatures we got in the seventies, eighties, and nineties.That helps a lot. These people aren't perfect, but their mistakes aren't mistakes of psychopaths. Their "faults" are very normal. A little girl puts her nose in where it shouldn't';t be. A teenage girl swims with a boy her mother disapproves of. A scuba diver does a "Hudson" and panics when he sees the creature, although there was nothing he could do to save his buddy any way, and then he is guilt ridden and emotionally charged, wanting to go back.These are things we like to say we wouldn't do, but in reality, we very well could do. Some people pay with their lives. Some get a second chance. This is a role model for Christian movies in that it shows a "god who is no respecter of persons".Meanwhile, while some of the movie is "formula", it is "well done formula". The characters are enjoyable, although I wasn't impressed with the acting of the little girl. For that, I guess we can blame her "coach".Still, we get good "atmospheree", with the boats on the Salton Sea, the lab, and the sea shore suspense. A slightly better than average movie. Not great, but this would be a top twenty film in any year between 1970 and 2000, but that was the pathetic era of Hollywood. This was made in the golden era, where even B movies were made to be entertaining.