Fallout star's new mermaid horror-comedy with 100% Rotten Tomatoes score is an eerie, endearing must-watch

A movie pulling in a perfect, 100% Rotten Tomatoes score is a rare thing these days. As rare, you might say, as finding a mythical sea creature bobbing off a Floridian marina – and yet, with Mermaid, Fallout star Johnny Pemberton manages to do both.

Written and directed by Tyler Cornack, the surreal horror-comedy is reminiscent of a slice-of-life Sean Baker flick, as it drops us into the world of Doug Nelson, a drug-addled dude who works at a neon-lit bar that's essentially a strip club meets Seaworld. He knows all there is to know about salt-water fish. Humans? Well, they're a little trickier for him to work out. After he's unceremoniously sacked for putting poems in his unrequited work crush's locker, Doug's life starts to unravel fast; his dealer, played by a terrifically funny, way-too-tanned Robert Patrick, is looking to collect an overdue $3,000 bill while his daughter's mother (Julia Larson) is desperate for him to be a more present father.

Buckling under the piling-up pressure – though you wouldn't know it from his distracted drawl and chilled-out demeanor – Doug drives a small boat out into the Atlantic and toys with the idea of doing something drastic. But he's shaken out of his stupor when he spots an injured mermaid, and takes her back to his rundown apartment to nurse her back to health. Chaos, as you might imagine, ensues.

In at the deep end

What's so tickling about the movie is that the "woman" he finds isn't some alluring damsel-in-distress with fins. Oh no, she's a flesh-eating scaly monster who bares her sharp teeth, snarls, and spits up black bile. Shots of her are used sparingly, oscillating between starkly bright wides where she's partly obscured, to darker, more close-up silhouettes, which gives the film a genuine sense of dread and tension. But, naturally, she's not the real villain here and Doug is such a sweetheart that he sees her as some sort of kindred spirit. "I've gotta be able to trust you and you gotta be to trust me. Trust. Otherwise, I don't think this is gonna work out", he urges in an early scene, before he dubs her Destiny. "You're probably scared. I'm scared. It's new territory for me. But as scary as it is, you're kinda making me feel some things, okay?"

It's Pemberton's sincerity amongst all the absurdity that makes Mermaid a must-watch. Initially a bully, Thaddeus, his ill-fated, mutating character in Prime Video's Fallout, has grown to become a fan favorite thanks to the actor's innate likeability – and it's impossible not to root for him here in much the same way, even if Doug is a bit of a creep and a deadbeat dad. As evidenced by my earlier Big Screen Spotlight features on Your Monster and Cold Storage, some of my favorite watches are where regular, kind of boring folks are thrust into crazy situations and as the actual baddies catch wind of Destiny, and try to capture her for reasons of varying degrees of twistedness, it's a chuckle-worthy delight to see Doug step up as her underachieving avenger. In a world where chosen ones and superpowered beings still dominate the big screen, I couldn't be more here for his hapless hero.

Despite being the main character, Doug acts as more of a straight man to the roster of zanier supporting players, however. Mermaid really shines – or should I say 'shimmers'? – in its more microscopic moments: Patrick's Ron filling Doug in on how his "mediocre wife of 35 gone done gay" or when he refers to the famous creator of Mickey Mouse as "Walter Disney". The fact that Ron's son is sporting board shorts and a neck brace for the entire 105-minute runtime. The awkward banter between Doug and his father's grandpa…

Kindred spirits

Mermaid's mix of humdrum and Odyssean antics is what makes it clear Cornack finds inspiration in Baker's work, but its pastel, neon-edged hues feel specifically The Florida Project-esque. It's a love letter to the Sunshine State in the same way the latter was; its characters running around and getting up to all sorts of mischief, like kids enjoying the last few hours of daylight. "I've been around this globe numerous times. I've slept everywhere that a man could possibly sleep. I've fucked everything that a man could possibly fuck. And until last night, well, I thought I had eaten everything," a particularly sinister figure explains to Doug in the final act. "No matter how many places I've been, I always manage to come back to Florida; it's the only place on Earth that can still kinda surprise me."

While Mermaid can be similarly compared to the likes of Napoleon Dynamite, Jared Hess's quirky coming-of-age tale about a socially awkward teen who vows to help his best friend become class president, and Guillermo del Toro's sci-fi romance The Shape of Water, it's a refreshingly original thrillride. As big-screen blockbusters like The Super Mario Galaxy Movie and Project Hail Mary clog up theaters this weekend, I urge you to consider splashing your cash on this one. You won't regret it.

Mermaid will be in select US theaters from April 8. For more on what to watch, check out the rest of our Big Screen Spotlight series.