worm id in live rock

Hello my name is Kasey and I am new to the saltwater hobby. I have been in the freshwater hobby for 10 years and have finally converted to the dark side . I currently have a new tank set up (2 months running) with live rock, a bicolour blenny and a PJ cardinal. When looking at my tank I notices...

I have these “worms” in a few spots in my 55 gal reef not sure what they are or if they are a pest or not.

Hey guys So we are a good few weeks into the 20 gallon and I have 6kg of live rock tank mates are Nasarrius snail, 2 red legged hermits and a turbo snail who is doing a great job on the algae clean up. The rock is covered in copepods but I noticed a weird tentacle earlier! There was a small...