The Devil's Mouth review: Forget the sharks, toxic friendships bite hardest in Prime Video's messy thriller

Ah, shark films, today. You just know it's going to be 1.5 hours of terrible decisions, and you might just end up rooting for the shark(s). If it sees such willing wanderers ambling into its midst despite all prior warnings, it will obviously think it's all-you-can-eat buffet.

And so, that's the thread holding Amazon Prime Video's Devil's Mouth together. It's still a step-up from Netflix's Thrash this year, and that isn't saying much. There's no Jaws like psychology here: it's a relatively easy watch even for those who can't stand too much gore. As the case is for any average thriller, you'll know who die first. Check the ones with the least personality and try to spin jokes at the wrong time.

Nevertheless, the real horror here in this film, is a toxic friendship, which might just lead you to a shark, if you can't put your foot down in time.

The film opens with five twenty-somethings holidaying in Thailand. They're close friends, so they say, but the first scene itself proves that wrong: albeit unintentionally, they leave their friend Sara (Kathryn Newton) in the ocean, attacked by jellyfish. She is rescued, of course, but her emotional wounds are deeper than the welts on her arms and legs.

The incident exacerbates the tension between her and lead bestie, Max (Lana Condor), who is bossy, controlling, and doesn't let anyone ever get a word in edgewise. However, she appears to have a few smidges of guilt and promises to look out for Sara more during their trip to the Devil's Mouth freshwater caves.

Her selfishness controls the narrative, even as they realise they're in shark-infested waters. As the friends soon learn, a shark isn't as dangerous as their own toxic friendships and their inability to say 'no.' If you can't afford to set boundaries even when death is swimming around, then what hope do you have?

So, even as the danger levels rise and they've discovered a gory death in the cave, they're unable to work as a team, to the point that their lead diver, Watt, swims away in frustration. The friend group can only talk in clichés and rhetoric that, literally, get them nowhere.

It gets worse.

Max has seen remnants of goggles and watched her friends being bashed around by sharks, including Gavin Casalegno's Greg, whose one personality trait is calling his mom at night (enough to make him disposable in a thriller), she can't loosen her hold of control until the very end. At one point, with the group's survival hanging by a thread and Watt begging them to move, Max plants herself and insists that she wants to see the last cave, thank you very much, control freak instincts fully intact even as the water rises. It's less loyalty than it is Max being unable to let anyone, even a shark, make a decision for her. By then, the shark and Watt are both done with the whole lot of terrible friends.

And as for the shark? The shark might have more personality and colour than the friends. Maybe, the shark's backstory would have been fun to hear.

Unfortunately, it just looms around the hapless tourists, watching their every move, even getting stuck rather cartoonishly in boulders, bringing to mind the shark in My Little Mermaid, chasing poor little fish, Flounder.

Here, it swims slowly to serve the plot, and sometimes it just decides to swim fast, because it can. The CGI is rather poor, so rarely does the shark provide any real jump scares. It seems to enjoy mind games too, taunting poor Watt, as if to say, "Now you see me... now you don't. HAHA, gotcha!"

The shark, to put it bluntly, is just a catalyst for exposing the fractures and fissures in an already broken friend group.

So no, the shark isn't the scariest part of this thriller. Nevertheless, The Devil's Mouth was entertaining to watch, if you have nothing else to do on a Friday night.

That said, the so-bad-it's-good tone wears off toward the end, and patience runs thin. The last 30 minutes feel like a walk through cement, as both Max and Sara struggle to escape, and finally, the lone survivor makes it out of the cave, bloodied and screaming in triumph.

Yay for you, girl... but five people are still dead? They might have been terrible friends, but can we be a little somber? Or is that not a thing anymore?

This film is the kind of watch you reach for when you need a very safe shark thriller. It's the one you want to watch with your friends, just for dialogue like "Hey man, you gotta Aquaman your way out of here" and some self-affirming chants that sound like 'I am special, I am the best', as the shark closes in.

It also serves as a reminder that you're really better off at home, and not wading into deep, shark-infested caves.