As mythical beasts go, unicorns aren’t exactly strangers to cinema, cropping up in films across the ages from Disney to Harry Potter. They’ve held a familiar presence in folklore for millennia, managing to transcend cultures, prancing through various countries’ mythologies for time immemorial – from 5^th century Greece to ancient China, and there’s even a reference to one in the Bible – and yet, you’ve probably never seen a unicorn movie quite like this.

In Death of a Unicorn, a new horror-comedy from writer-director Alex Scharfman, Paul Rudd and Jenna Ortega play father-and-daughter duo Elliot and Ridley, set to spend a weekend at the estate of Elliot’s billionaire boss, Odell Leopold (Richard E. Grant) – dying of cancer but keen to continue doing business ‘til the bitter end – and his similarly White Lotus family (Téa Leoni and Will Poulter). En route through the Canadian Rockies to the Leopolds’ mountain retreat, they accidentally collide with a creature of some sort. Initially unsure what the creature it is, it’s swiftly revealed to be none other than a unicorn foal, capable of inducing kaleidoscopic visions if you grip its horn. (It’s capable of much more too, but that’s for later.) This mythological encounter is quickly severed when Rudd bludgeons it to death, and the two continue their journey to the retreat, a little shellshocked, with deceased unicorn in tow. Once we’ve been introduced to the coterie of obnoxious characters that make up the Leopolds – including Will Poulter on pitch-perfect form as an abrasive swaggering tech bro – the unicorn comes back to life, eager to wreak revenge on the retreat’s inhabitants. Things take an even more brutal turn when the unicorn’s more ferocious – and substantially bigger – parents turn up.

It’s plain to see that violent unicorns are a rarity. As such, there’s something grossly entertaining and amusing about seeing such a famously docile creature transformed into the ultimate horror demon. This film asks, what if unicorns weren’t cute but completely demented and ruthlessly savage, and hellbent on ripping us to pieces in the most violent ways possible? And it answers that question tenfold. What’s more, the cast are perfect – every one of these actors can carry a film in their own right – and for all its inherent silliness, the script boasts some brilliant lines. Its attempts at satire on the rich don’t ever reach the dizzying heights of movies like The Menu, but it’s an enjoyable look at how a group of elites might act when confronted with a situation like this and view it as a potential goldmine.

Where it falters ultimately is its reliance on the formulaic: the characters, whilst entertaining, are generally little more than stereotypes. Richard E. Grant is basically an updated version of Mr. Burns, the rest of his family one-dimensionally mercenary – simply put, very bad people. Upon discovering that unicorn blood has the power of healing every known ailment, from cancer to acne, their immediate response is to see dollar signs, and it’s every bit as predictable as you’d imagine. Meanwhile, Ortega is the sullen teenage girl no one listens to who has a special, semi-telepathic connection with the otherworldly being of the title, and her dad is a weakling torn between being a good father and kowtowing to his boss. Strangely, it’s the exact same dynamic Christina Ricci and Bill Pullman had in the 1993 Casper movie, and fittingly so, since Ortega’s career often feels Ricci-esque in its persistent paralleling. If they ever do another remake, she feels like the obvious choice.

Then there are the unicorns themselves. Without sounding too Maude Flanders about it, the violence they enact on our hapless cast feels wildly over-the-top and unnecessary. Do we need to see a unicorn cram its horn through the neck of one character, or crush the skull of another? It feels gratuitous and doesn’t serve the plot much. Something else is painfully apparent here too – the CGI just isn’t up to scratch. Naturally, as with a lot of post-90s monster movies, the film pays several homages to Jurassic Park – including a notable giant-eye-against-the-jeep-window shot – but this unfortunately highlights just how shoddy the CGI is in comparison. Spielberg’s dinosaur opus came out 30 years ago, but the animatronic-graphic-mix of that film feel miles superior to here. It jerks you out of the story, and you can’t suspend disbelief enough to be convinced Ortega and co aren’t just staring at a few greenscreen rags on a stick. It indicates that in the SFX world, an overdependence on CGI means we’ve majorly regressed.

As the credits roll, you wonder how this story would have fared if told in a less commercial fashion. It would be interesting to see what directors like Yorgos Lanthimos, Michael Haneke or Julia Ducournau might have done with the subject matter. Perhaps their approach wouldn’t have been quite so predictable, the characters more clearcut, less divided into good and bad. There’s enough here to make Death of a Unicorn work, and the cast carry it along perfectly well. It’s a wild ride, and entertaining despite its pitfalls – yet all too often feels like a swing and a miss.

Death of a Unicorn opens in the UK and Ireland, from A24, on 4 April