Coilodesme bulligera is a small, ephemeral brown alga (Phaeophyceae) in the family Chordariaceae, characterised by its hollow, inflated, saccate to irregularly bullate thallus—properties reflected in both the generic name Coilodesme (meaning 'hollow band') and the specific epithet bulligera (meaning 'bubble-bearing'). The species forms delicate, pale brown, irregularly blistered or pouched blades that are hollow internally, typically attached to rock or other algal substrates in the low intertidal and shallow subtidal zones of cold northern seas. Coilodesme bulligera has been recorded from Norwegian coastal waters, and similar species in the genus occur across boreal and arctic Atlantic and Pacific coastlines. As a brown alga, it is a photosynthetic primary producer in coastal ecosystems, contributing to the food web by supporting invertebrate grazers and providing habitat structure on rocky substrates. The genus Coilodesme is poorly studied compared to more commercially significant brown algae such as kelp, and limited ecological data exist for individual species. The species is classified as Data Deficient by the IUCN, reflecting insufficient data to make a reliable assessment of its conservation status. Taxonomic boundaries within the genus require further molecular and morphological investigation.