OH, FOR GOODNESS' SAKE STOP IT. CONTAINS SOME SPOILERS.
In the last few years, the legendary Roger Corman seems to have developed a bizarre predilection for randomly bolting together animals that are completely incompatible with each other and then making low-budget horror movies about them. Dinoshark, Dinocroc, Sharktopus, and now this: which you'd think was some kind of mutant crossbreed between a piranha and an anaconda but actually turns out to just be an extremely big snake with no piranha traits whatsoever. (In fairness, Camel Spiders isn't about eight-legged dromedaries, fun though that might be; they are just a peculiarly named kind of spider.) What's next? Komodohorse? Hamstercow?
The (very) basic idea of Piranhaconda is that there's a giant snake on the loose: it hibernates for years at a time, which is why it hasn't been spotted recently, but it's awake now and rampaging through Hawaii attacking people so hard that they're instantly reduced to a red vapour. The unfortunates wandering obliviously around its nesting ground include a film crew halfway through shooting a cheap slasher movie, obsessed scientist Michael Madsen (!), a bunch of crooks taking everyone hostage and a pair of bickering lovers. Since Madsen has stolen one of the eggs, you'd expect the piranhaconda to be on the trail, except that it isn't: it hangs around the jungle munching people who've nothing to do with the egg while Madsen is sitting in an abandoned shack. And it's pretty obvious, so it's not really a spoiler: since there are eggs, there must be a second snake....
It's obviously twaddle: four entirely unconnected groups of people are all wandering around on an island that's larger than Berkshire, yet they keep running into each other. Why does the fictional director abandon shooting on the grounds that they're losing the light when the entirety of the film takes place in blazing sunshine? And can Madsen really be so thunderously stupid as to try and steal an egg from a 100-foot snake that's already killed his two colleagues in front of him? Badfilm connoisseurs should note an early scene where the monster takes down a helicopter, but the sad fact is there's little artistic difference between the cheap slasher movie made by the doomed film crew and the cheap monster movie we're watching.
Yet while the film really isn't any good at all, it's not so awful as to actively anger you. Mostly it's put together reasonably well enough and less than 90 minutes it doesn't drag. And at this stage there's really not much mileage in pointing out that all the monster effects are done with dodgy CGI that simply looks like it's been pasted into the film on the computer afterwards (because it has). Getting these things to look even halfway convincing takes time and money, and films like Piranhaconda have neither. But the Syfy Channel, Roger Corman and director Jim Wynorski are literally churning these things out: Piranhaconda is just one of four films Wynorski directed in 2011. I'd submit that the films would be better if everyone slowed down and stopped tossing them out every couple of weeks. Quality over quantity.