This is one of the most fondly remembered of the ‘giant monster’ films popularized by THEM! (1954) and, in hindsight, still ranks among the best of its type. I had first watched it on late-night Italian TV in my early teens and recall being somewhat let down; I was more receptive towards the film on a secondary viewing – since it’s clearly a notch above the other titles in the “Classic Sci-Fi Ultimate Collection” set (save, obviously, for THE INCREDIBLE SHRINKING MAN ).
Anyway, the film echoes THEM! (which is the superior effort, by the way) in several aspects, but is sufficiently different to stand on its own merits. Actually, it’s a logical extension of the earlier film – because even if we have only one mutant monster here (not necessarily a budgetary imposition), it’s an insect species that’s far deadlier than the ants seen in THEM! Besides, even if the resultant growth in size is man-made, it’s the product of an experiment involving a genuine concern for mankind’s future (the creation of synthetic food, which would eliminate the problem of famine facing Earth’s ever-growing population); the fault, then, lies in man’s own impatience at achieving his goal!
An original subtext to the central narrative – and which, as Leslie Halliwell opined, is perhaps even scarier than the idea of an over-sized spider – is the fact that the experiment is eventually conducted on human beings, causing acute acromegaly (shown via amusingly exaggerated make-up)! The cast of TARANTULA may not be as prestigious as that of THEM!, but it’s certainly agreeable: regular Universal hero John Agar (who’s always a doctor of some kind in this type of flick) and his sidekick Nestor Paiva (here in a bigger part than usual as the sheriff); we also get a sexy heroine in Mara Corday (she later did similar duties in two other ‘giant monster’ pictures, namely THE GIANT CLAW  and THE BLACK SCORPION ), and ever-reliable character actor Leo G. Carroll as the misguided – and eventually deformed – scientist.
While the special effects of the rampaging spider seem variable at this juncture (although rather better than I recalled them), they were probably considered state-of-the-art back then. Even so, perhaps the film’s best sequence is the one where the monster attacks the doctor’s house and lab, crushing them under its weight; the image of the giant spider’s eyes peering into Corday’s window is still creepily effective (and must have given 1955 audiences veritable nightmares!). The satisfying climax (featuring a bit by a very young pre-stardom Clint Eastwood) first sees Agar, the authorities and the townsfolk unite in an attempt to deal with the arachnid their own way – but, when this fails, they call a nearby military base for help (whose speedy intervention, an obvious plug to the resourcefulness of the U.S. Air Force, proves infinitely more successful).