Help with ID of plant pest

[SarasotaSunset]

I noticed I have what I think is some form of plant that has been added to my tank. It seems to also sting corals. In the photograph look toward the top of the photograph. Resembles a pin with a head, long piece that seems to have a head on top. Anyone know what this is?

http://i30.photobucket.com/albums/c307/SarasotaSweetie/Reef/reef_zpsb090594f.jpg

[cloak]

Hydroids perhaps?

[SarasotaSunset]

Thanks Cloak. I found some other threads and did some research and the only thing that doesn't match is the top part. It seems all the Hydroids resemble a snowflake on top. I put a macro lens on my IPhone last night and these don't resemble snowflakes, they basically just resemble a ball.

Anyone else out there have any additional ideas what these could be?