Pycnotheca mirabilis, The feathery hydroid, is a colonial hydroid in the family Kirchenpaueriidae.

[2] Feathery hydroids are often white and grow in crowded colonies resembling upright feathers.

The stems may grow to 3 cm in total height.

The reproductive bodies are found at the base of the stems and resemble beehives.

[3] This colonial animal is found off the South African coast from False Bay to KwaZulu-Natal, as well as around the Indo-Pacific rim and Vema Seamount.