Likely hitchhikers?

[wet_algae]

Looking for possible id's

I removed the worm because it didn't match up with anything i could find (looked like a couple bristleworms but the tail and antennae were different).
The thing embedded in the rock almost looks like a scallop to me.

 

[serval]

The worm reminds me of pictures I’ve seen of Eunice worms. Not all are bad but I’d get rid of it. It’s this feelers at the head that worry me.

The thing in the rock could definitely be a bivalve but I don’t know what kind. Scallop seems unlikely (?).

 

[Elisabeth GER]

https://reeflex.net/?kategorieID=79#sycon

 

[wet_algae]

https://reeflex.net/?kategorieID=79#sycon

these are so cool looking. Do you think it'd last? I've had the rocks for over a month and dose phyto daily

 

[serval]

Some sponges can survive. I don’t know about that particular one. There were a bunch of sponges on my gulf rock but after a year only the yellow one and a grey one are still there. Sadly a nice red one disappeared.

 

[Abominable Snow Crab]

Those look like what we called pineapple sponges. Also most likely a mussel and the thing making the sand tube will be a worm of some type. Good to have imo. Not sure about the worm on your glass - I wouldn't worry about it though, personally.

 

[Elisabeth GER]

these are so cool looking. Do you think it'd last? I've had the rocks for over a month and dose phyto daily

Sycon sponges can survive in an aquarium. They are most commonly found in the filter tank. I have never seen any larger than 1 cm.

 

[EnterName]

https://reeflex.net/?kategorieID=79#sycon

these are so cool looking. Do you think it'd last? I've had the rocks for over a month and dose phyto daily

Check out page 5, post #83 (https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14427946)

They are very common and do very well in reef tanks. You will find them in cryptic zones where light is very limited so they will never harm corals in contrast to some other sponges. Every time I dose phytoplankton I can see them change color to a slight green from all the small microalgae they collected they help to filter the water a lot and fast as their numbers grow.

The tube on the top right of the last image might just be the home of some tube-dwelling crustacean or worm. Doesn't look like an issue.