if you can look close enough than they might actually be little feather dusters i have them all on the back of my wall. they started real little white dots, they gotten bigger not huge but big enough that i can see they are feather dusters.
it does look like spirorbid worm but on some of them i can see the feather duster!! so i dont know!
bsmith219 looks at the thread scotts put there it might help out alot.