Red Growths in Tank?

[KyRo]

I’ve never noticed these before tonight but without the lights on I saw more than one spot on my rocks with red growths. I first thought that it was coralline algae finally showing up but I was under the impression that this algae was more flat and not pronounced. This stuff can be scraped off, kind of like a scab if I had to describe it. On piece was even coming off in a branching type way. I tried to take pictures the best that I could but it was not easy. Does anyone know what this might be? I took a piece off and it is very hard to the touch.

 

[ichthyogeek]

When you say it's reddish, does it have an almost tentacular look to it? From your description, it sounded like mini feather dusters.

But from the picture, it looks like you broke the siphon off of a vermetid snail...