Electra crustulenta forms encrusting mats, large erect clumps or foliage-like cylinders around the stems of plants. Individuals (zooids) of the colony can be elongate, rectangular or oval, separated by narrow grooves and are approximately 0.5 mm long and 0.3 mm wide. The upper surface (frontal surface) of zooids is covered by about three quarters membrane and one quarter calcified shield (gymnocyst). The zooids are white and the operculum (door to the zooid orifice) is opaque white. Electra crustulenta zooids has crenulate margins with a single short spine.