Dictyoceratid sponges do not have the usual mineral spicules (rod-like structures that make up many sponge skeletons). Instead they are made entirely of elastic spongin (protein) fibers organized into networks. This makes their bodies tough and flexible. They are easy to squish, but hard to tear. The surface of their body is typically raised up in little cone-shaped points, making it look like they have goosebumps. The bumps are actually projections from the underlying skeletal fibers, and in some species the bumps are expanded into an armor-like covering. Dictyoceratids have the habit of incorporating debris (such as sand grains or spicules shed by other sponges) into their skeletons, making them harder.

Sponges do not move around much; they are considered to be sessile or fixed in one place. However, research has shown that some sponges can move slowly by shifting their cells in a coordinated fashion. They can reshape themselves to crawl along the seafloor or other surface. They extend parts of their bodies and contract others to achieve locomotion. However, if you attempt to watch a sponge moving, you will likely be disappointed. At best, they move tiny distances, like a couple of millimeters per day. Juvenile sponges are much more mobile. A sponge larva is a little ball of cells with hair-like extensions (cilia or flagella) that allow it to paddle around for a few days until it finds a place to settle down. Once settled, its cells transform to be more appropriate for a sessile organism.