Here is a hitchhiker that has been a pain..... literally. The hair like things on this guy are sharp and stick in your fingers. You do not know they are there unitl you bump that finger on something.
The closest Id i have got on these was a Homotrema Rubrum
Actually, it is a mostly dead or dying sponge. This is very common in the wild. The spicules are silica (and if there's some toxicity involved with some live sponges) and are exceedingly sharp.
