- Kingdom: Animalia
- Phylum: Echinodermata
- Subphylum: Asterozoa
- Class: Asteroidea
- Order: Valvatida
- Family: Goniasteridae
- Scientific name: Hippasteria phrygiana
- Norwegian: hestestjerne
The color is yellow or orange and the surface is covered by small, white warts or tubercles. Along the edges the warts are prolonged into small spines. Each spine is sitting on a shell plate. The rigid cushion star can grow to a diameter of 20 cm. It has a large central disk.
The rigid cushion star can be found on depths between 10 and 100 metres, on a wide range of substrates.
It is widespread in the Arctic and North Atlantic Ocean, both on the American and European side. In Europe it is registered as far south as the British Isles and Holland.