Please help me identify this "thing"

[JosephNg]

Hi everyone, this webbing-like creature appeared today in my sump at ~9pm. It was not their yesterday as well as today in the morning. It did not move as I inspected but I'll check it again tomorrow. Is it bad?
Thank you.

 

[vetteguy53081]

Looks like poriferan sponge
Get under it with an old credit card or plastic putty knife and gently lift it

 

[JosephNg]

Looks like poriferan sponge
Get under it with an old credit card or plastic putty knife and gently lift it

Does it spread quickly?

 

[vetteguy53081]

Does it spread quickly?

It can be evasive- yes

 

[BiggestE22]

Is this bare bottom?

 

[JosephNg]

Is this bare bottom?

This is where the water comes down first so I only place 2 layers of sponge on top of it