Orange thread-like thing?

[joonahrae]

I just purchased a clove coral frag, and it came with this orange thread-like thing at the base of the coral.
Is this part of the clove coral's natural growth, or is this a hitchhiker that I need to treat to remove?
I tried removing it with tweezers, but it felt really stuck on the coral.
It didn't seem to change shape like a nudibranch or a flatworm would.
The orange thread does seem to be growing.

 

[MERKEY]

Possible sponge, they do stick to the coral pretty well once growing on them.