Giant Gila Monster (1959)

"There are parts of the west that are still unexplored" this film's introduction informs us "where the gila monster dwells.  And who knows how large they could grow?".  Well, Mr Narrator Man, given the name of this movie, I'm guessing your answer is "pretty darn large".

We then switch to two teenagers necking in a car.  They don't slather themselves in BBQ sauce, but given the kind of film this is, they might as well have done.  Their vehicle is knocked down an embankment by a sudden attack.  All we see of the culprit is one large foot swatting the camera, but I am going to display my deductive reasoning skills and posit that the culprit will prove to be an uncommonly large lizard.

The film will now take a long, long, long diversion into teen soap opera.  Probably because having a bunch of kids awkwardly attempt to act is a lot cheaper and easier to film than even the embarrassingly basic "effects" on offer in this film.  We get a lot of blather that amounts to "Chase is a good kid really, but mean old Mr Wheeler keeps treating him like some kind of hoodlum".  It's probably because of that hot rod he drives.

See the way I worked in a mention of Chase's car, there?  The film will not be so subtle.

Anyway, the missing male teen is Mr Wheeler's son, and he insists the sheriff gets out and find the lad.  And the girl too, if possible.  The sheriff decides to do this by talking to Chase.  Because this movie needs to circle back to Chase every four minutes or so, apparently.

Anyway, Chase and some friends eventually find the missing car.  In the scene in question, the camera keeps cutting between the kids and a lizard, but the shots of the latter were so poorly constructed that it took me several cuts before I twigged to the fact that this was supposed to be the giant monster of the title.  There was a real need to include a model of something in the shot to establish that this was supposed to be something other than a regular lizard.

Anyway, Chase & Co somehow fail to notice the bus sized monster in the bushes.  They'll hear about it later though, when it derails a train and attacks the passengers.  By which I mean "crawls over a model railway set while screams are overdubbed into the soundtrack".

Then we get another long, long, long bout of soapy drama as Chase launches his career as a teen pop star.  Eventually the monster decides to interrupt proceedings which means we can finally get to the 'climactic' scene of Chase loading his car with nitroglycerin and blowing the lizard to pieces.  Chase himself, unfortunately, jumps clear before the explosion.

This doesn't even manage to be bad in a good way.