sliily confused clownfish

I have a clownfish tha seems convinced that one my large hawaiian
feather dusters is some sort of funny looking anenome. She likes to swim
through the feathers of it's crown, and I have seen her dropping food to it.

At first the duster used to retract whenever the clown would swim though
it's crown, but now it seems quite used to it.

If you put your hand in the tank and try to move the rock the duster is
attached to, the clown will start nipping at your hand. If you don't put
your hand near the duster, she leaves your hand alone.

There are two dusters right next to each other, and she only does this
with one of them. This one particular duster seems to be HER duster. She
never does this with the other duster, which is maybe 3 inches ways
(close enough that the crowns touch) It's the only the female of my pair
that does this - the male seems "skeptical"

Anyone ever seen this sort of behavior before? Clownfish trying to host
with something that is non-cnidarian? I have heard of them hosting with
ricordias, mushrooms, frogspawn, etc, but never a duster worm!