Red Coral???

I was starting to think as to what type of hard coral would grow under the low light conditions I have....makes much better sense it's a snail now. My tank is in no shape for any sps or lps, I've conditioned it for softies only.

When you say they spread fast, how quickly are we talking about, I've been watching these 2 for a few weeks now and the growth is almost missed, except for the fact I payed close attention to them, one would hardly know they existed. Do they stay relatively small?