Any guesses what these are?

[LI2NC]

Anyone know what these are? There are 5 of them now attached to my live rock. I tried to take good pics but this is the best I have got.

Any guesses? My wife noticed then a few days ago, I had never seen them before she pointed them out. Good for the tank? Bad for the tank get them out ASAP?

 

[Auquanut]

Looks like pineapple sponges. Filter feeders that tend to disappear over time.

 

[MoshJosh]

Big guy is pineapple sponge, small guy is spirorbid worm. . . both harmless.