A. horridus may refer to:
Abdopus horridus, an octopus species in the genus Abdopus Acanthopholis horridus, an ankylosaurid dinosaur species that lived during the Early Cretaceous Period around 100 million years ago Acanthosicyos horridus, an unusual melon species found only in Namibia Argosarchus horridus, the New Zealand giant stick insect, a stick insect species endemic to New Zealand
See also Horridus (disambiguation)