- Kingdom: Animalia
- Phylum: Chordata
- Subphylum: Tunicata
- Class: Ascidiacea
- Order: Stolidobranchia
- Family: Pyuridae
- Scientific name: Halocynthia pyriformis
- Norwegian: pæresekkedyr
This is a solitary ascidian, but appears occasionally in large groups. The body may reach a height of 10 cm. The color is red or orange, sometimes with pale, longitudinal stripes. There are two siphon openings on the top. The openings are almost quadratic with four distinct corners.
It can be found on almost any substrate from the tidal zone and down to a depth of 600 meters.
It is widespread in Arctic and North Atlantic waters, both on the American and European side.