El Ataque de los Esternocleidomastoideos Asesinos

A biology student's thesis on muscle regeneration goes horribly wrong when his experimental serum mutates the sternocleidomastoid muscles of lab rats into autonomous, neck-twisting predators. As the creatures escape and multiply across Barcelona, a mismatched team—including a skeptical police inspector and a conspiracy theorist gym owner—must stop the invasion before humanity loses the ability to turn its head. This 2026 horror-comedy sci-fi mashup blends body horror absurdity with frantic chase sequences through iconic city landmarks.