I need ID help please

[craigdon]

The first picture is of something growing under my hammer. It is a white rubbery looking growth. I can't tell if it's attached to the hammer or the rock under it.

The second picture is a grayish white(although it looks more blue in this picture) line growing around the rock. This showed up once before, but then slowly disappeared.

Any ideas what these are?

[camelcruiser]

Pictures aren't very clear but looks like a sponge.

[Origami]

The second picture shows what appears to be a sponge of some sort. Watch it. Some sponges like these (with tendrils) can become invasive pests if they spread too much and too quickly. Not all sponges behave like this, though, so just keep an eye on it and, if it becomes a problem, pick and scrape it off. I can't tell what you have in the first picture because it's blurry. 

[craigdon]

Thanks for the feedback. When the hammer recedes a little I'll try to get a clearer picture.

Under another rock in the back I have what looks like to white cotton balls. I assume they are some kind of sponge also, but it's to far back to get a picture.

[gmerek2]

I have the cotton ball sponge also and also the two sponges in your first pictures. They are filter feeders and should help your tank. I don't have any issues with them spreading yet.