Spirobranchus giganteus

I think Spirobranchus giganteus is the most interesting fish from the Gulf of Thailand. This creature is the most interesting creature of the Gulf of Thailand because the shape of it is like a christmas tree. I have never seen any worm this beautiful as the Spirobranchus giganteus. Every time I think of the worm, the word "ew" comes up in my mind, but for this type of worm, I found it beautiful and interesting. This type of worm has many colors; orange, yellow, blue, and white.

Questions I have about this organism:

1. What is it made of?

2. How can they form a christmas-like shape?

3. How did they protect themselves from the predators?