pontiac90 said:
Not really, Spongebob is made of sponge, but isn't an actual sponge (like the organism). Though Patrick Star would be since he's an actual seastar (same goes to Sandy, Mr. Krabs, Plankton, etc.) so they would be furries (unless I'm misreading the question, which I feel as though I am).

he actually is a sea sponge in canon, he just looks like a kitchen sponge for some reason.