Werid red sea sponge things on glass

[Cnidoblast]

Does anybody know what these are and if they pose a biological or chemical hazard to my aquarium?
My nitrates are at like 20 ppm and I am due for a water change soon so I want to know if I should suck them out or not and if the waterchange will help clean up my system a bit (also gonna be switching to lower nitrogen foods like pe mysis soon)

 

[KJ]

Harmless filters feeder nothing to worry about.

 

[Cnidoblast]

Would anybody be willing to dive in and find the species name of this organism? Just curious