Thelocactus setispinus, known commonly as Hedgehog cactus or the Miniature Barrel Cactus, is a cactus in the genus Thelocactus belonging to the family Cactaceae. Thelocactus nidulans is globe-shaped to short cylindrical cactus about 8 inches (20 cm) to 12 inches (30 cm) wide and up to 60 centimetres (24 in) tall. The 12 to 15 radial spines are needle-shaped, bright, brown or white and up to 4 inches (10 cm) long. The 1 to 3 central spines are longer and stronger, straight and curved like a hook at the tip. The flowers are orange, dark yellow, magenta, or violet with a red center, about 7 inches (18 cm) long.