Weird Foggy Thing On Live Rock

[Mwag]

Hello all. Just a couple of days ago, I noticed that there was a weird white foggy thing growing on my Live Rock. I don't know what it is and assumed it was some kind of hitch hiker but does anyone know what it actually is? I have a picture below. My tank is cycling so there is nothing in the tank but I am at the end of the cycle. My Nitrite just dropped to zero.

 

[Gweeds1980]

Not a great image, but going by the translucent 'chimney' I'd say a sponge.

 

[Mwag]

Do I need to remove it or can I just leave it be?

 

[Judy Carley]

tunicate?

 

[DancingShark]

@Judy Carley might be right.
They look transparent and have the same shape.
And welcome @Judy Carley

But this is about a year old lol.