Please help me know what this is.

[CoralBeauty13]

I opened my Sump today to see all this stuff. They look like little rice grains, with three or four tentacles on the ends. The head is stuck to the glass, and the tentacles are at the end.It was not there two days ago.
My parameters aren't great, only nitrates are up a bit, but everything else is on point. There has only been two new additions to the tank, as in hard coral, that i dipped and acclimated for a while before putting it in. All my fish look good, and I see none of this inside the tank, but it is full in the sump. I have noticed a bloom in little star fish, the tiny whitish/grey ones, but they are not new..there has always been a few. Do not know what it is and it has just happened. Please if anyone knows , help me.

 

[Newsmyrna80]

Nothing to worry about. These are filter feeders... Completely normal

 

[Mattewell]

I have a million of those things in my sump... they seem to be sponges of some kind. They should be harmless.

 

[downbeach]

Sycon sponges, AKA Pineapple, Q-tip sponge, harmless filter feeders. Too many may indicate excess nutrients in your system.