The Breadcrumb Sponge, Halichondria panicea, is hugely variable in shape, form and colour. It maybe quite massive as in the picture. It can be green, pale buff or a distinct yellow and often produces columns like chimneys. It is widespread around Britain both on the shore and in shallow waters in a variety of water conditions. Smells of sulphur when broken.
St. Abbs Marine Reserve, Berwickshire. Scotland