Hammer coral care and maintenance

[MindBurst]

I saw something weird with my hammer coral today - it had this 1-inch brown stuff coming out of the center.

Got out of the shower, came back, and it was gone. I'm wondering if it was just a poop or if it was getting rid of extra zooxanthellae? Wish I'd taken a pic of it, but here's my coral - he's been looking happy and opening up a lot.

http://imgur.com/qwQEbFT

[Fable29]

Could've been a bit of floating debris, maybe even fish poop that just got caught up on the coral. If it looks fine and is opening up normally, I wouldn't stress about it.