New tank - what is this plant?

[JWGarber]

I setup a brand new tank just about 5 days ago. Last night my girlfriend noticed a small plant growing on my base rock. What is it? Anyone know?

I have no clue how this plant got there. The seed must have hitched a ride in a dry rock.

See attached images. Hopefully its a beneficial plant of some sort.

Sorry for the picture quality. It was hard to get a decent shot.

 

[phobos2deimos]

Couldn't tell ya from the pics, some sort of Caulerpa? Maybe put that rock out on its own just in case it's a nuisance?

 

[JWGarber]

It vanished lol.. No clue where it went. I know it was sprouting from a tiny black seed.