Something spawning in my tank??

[lissalou3282]

Anyone have any idea what this is?
Little white thing came out of the rocks and started releasing a milky white substance in the tank for about 30 minutes then disappeared.
I have never seen it before.
looks like whatever it is it’s spawning in my tank. Any ideas?
I’m hoping the video works cuz it’s really hard to see in the pics.

 

[vetteguy53081]

Looks like a sponge but everything very white to tell
If in doubt- pull it out