With its rosy, sun-drenched colour palette (at least initially), Carlota Pereda’s spiky Spanish horror understands girlish anxiety so well that it could comfortably be a coming-of-age pic. Behind the glass counter of her parents’ butcher shop, Sara (Laura Galán) keeps a safe distance from the cool-girl clique which mercilessly makes fun of her weight. Highly aware of her body, Sara’s self-consciousness is exacerbated by an overly protective mother, who watches her every move. As if growing pains aren’t bad enough, Richard Holmes’s burly, oddly charismatic serial killer wanders into the small Spanish town and starts abducting her bullies. Talk about awkward!

Weaving together grindhouse thrills and adolescent dilemmas, Piggy has a dark humour that proves deliciously entertaining. Shots where Sara tries to hide her knowledge of the bullies’ disappearance from her overbearing mum are framed with the same nail-biting suspense as when she stalks around her twisted saviour’s macabre slaughterhouse. Issues such as body shaming are also explored without didacticism. In contrast to lesser horrors that attempt to be socially conscious, Piggy is much more specific and detailed in how it builds moods and atmosphere, especially the gossipy dynamics that run rampant in a tight-knit community.

Galán is also a delight to watch, a rare instance where an actor accurately conjures up the fidgety confusion of a young girl. Her character might be indebted to the slasher film’s long line of virginal, awkward teenagers, but Galán’s multidimensional performance ingeniously avoids facile ideals of female empowerment. She is far from a badass protagonist, but her faults are as endearing as her (gradually built) strength.

• Piggy is released on 6 January in cinemas and on digital platforms.