The charm in many old grindhouse horror movies is how singularly stupid the idea is compared to how seriously the filmmakers and stars seem to be taking it.

The first disconnect is that Frogs isn't really about frogs at all but nature itself (specifically reptiles and amphibians) taking revenge on humanity – or at least the humanity holed up on the rich island estate of the Crockett family.

Environmentalist photojournalist Pickett Smith (a ridiculously young Sam Elliott – everything from his trademark downturned mouth to the name of his character making him seem like an old man in a young body) is nearly run over by some freewheeling members of the local Crockett family in their speedboat while investigating toxic sludge – the only passing explanation for the nature-gone-wild premise.

The guy driving is a bozo with 'early victim' written all over him, but his pretty sister takes an altogether unconvincing and too-convenient liking to Picket, insisting he stay on the estate with the huge family and celebrate the birthday of the cranky family patriarch the next day.

Pickett decides to hang around, and it's overnight and into the next day that things go wrong as the scaled inhabitants of the island start attacking. First the groundskeeper is found dead, then everyone from the crackpot old Aunt to a long suffering brother in law go off and get topped by animals in ways that are as scary as rubber toys and almost as ridiculous.

In one scene of a man taken down by a alligator, the effect is achieved by having a real alligator death roll a shop window mannequin and then tying it to the animal's back so it looks like it's making off with a dead body (when it's probably trying to get away in terror).

In another a guy walks through a huge spider web and proves himself the most useless character on celluloid as he just falls down squealing like a six year old girl while spiders fall all over him, biting him to death in only about a minute.

But the frogs of the title take the cake. The ghoulish one sheet shows a huge, Tiddalik-style monster with a human hand emerging out of its mouth. You might be looking forward to flesh-eating frogs the size of Citroens, and although it would have been a hoot with a film of this budget, their sole killing power seems to be to find someone who can't get away and jumping-on-them to death.

Like a lot of 'classics' of the era, there are some laughs at the cheapness of the production but it's none too exciting or entertaining.