It appears to be some sort of plant. Looks like a stalk with a single leaf at the top. They are about 3/8" tall. Does any one no what it is. Does anyone know if the yellow blob to the right of the the little growies could be Erythropodium aka encrusting gorgonians?

hey,,,, i have the same thing growing in my tank too...they grow in groups...i've had them for 2 years +...never seemed to harm anything..i was actually thinking about taking the rock they where on and removing them... any id on them would be great....

Hydroids?

Looks like some type of star/clove polyps

Darren nailed it- hydriods.

Check here:

http://www.reefs.org/library/aquarium_net/1097/1097_2.html

Yep. Hydroids. They look neat, but can grow to nuisance quantities. They can also sting corals and, given sufficient contact, irritate human skin as well.

Kill them while you can.

I do not have these but, ill ask the question for him. How do you kill them? Same as aptasia? Lemon Juice?

I had a small colony grouped together on a piece of LR. I made a slurry out of kalk paste and ro/di water and covered the colony. They did not come back.