Harp sponge (Chondrocladia lyra). The newly described invertebrate isn’t so benign. Rather than filtering the water for bacteria and other single-celled organisms like most sponges do, the harp sponge employs Velcro-like barbs on its vertical branches to snag tiny crustaceans called copepods as they swim past. Then, cells specialized for digesting prey surround the captured swimmer and slowly start to digest it.