sponge or nano reef aquarium detritus?

Hi I have this sponge as something that sticks to my rock and keeps playing. Every time I brush OFFF everything seems to come back is rubbish, feels like a sponge on the rock. Finnish my tank is cycling, but these things always come back

Can you could get a picture of her? could not be any bubble algae?

Nano Lagoon (11a): Keep it Clean