Oops, sorry, I meant artificial as in not alive, as in plastic or fabric.
I know clowns frequently adopt various corals as hosts, since I can see it at the LFS [a clown rubbing itself on a very realistic looking tongue coral used to give me a good laugh, seemed the tongue should be doing the work, not the fish].
Perhaps clowns would like spawning media meant for shrimp?
I found a photo of a DIY spawning mop made from green acrylic yarn. That looks cozy.