ID this nocturnal hitchhiker
 

Theres this weird hitchhiker that comes out at night out of this point in my rock.
He comes from this white tip that kinda erects outta the point of the rock outta a white tip during night time. And every couple seconds he'll kind of bring up and open his "fan" almost like a feather duster does, but imagine its only HALF of the tail (like a feather duster but split in half) then once he brings it up and open and he'll kind of scoop it back in repeating this over and over.

sorry for the bad pictures but its hard to capture this guy. His color is like a really light white, perhaps pretty much clear.

those stll belong to the same family as the feather dusters you are familiar with.

Can't really make anything out in the pictures, but you've described a barnacle. They're arthropods and are harmless filter feeders. Imagine a shrimp in a box (that is actually its nose believe it or not!) that feeds by sticking its legs out and sweeping them in to its mouth.

Pictures are hard to make out, but +1 on the barnacle ID based on what you've described.

Haven't had enough wine yet to make sense of the pictures but I'm giving a +1 on barnacle (the 'half feather duster' and the in and out are a give away).

impossible to tell from the pictures.... need some better ones

ya i myself think its a barnacle now. I did some more research and watched him for over 30 minutes last night lol