is this a pineapple sponge? or something else

so i spotted this sucker on another piece of live rock. its about an inch long, maybe a little bigger. it basically looks like a white cocoon with a mouth. and its huge.

i also noticed another 10 or so other ones on the under side of the rock, but not nearly as big as this sucker, theyre only about 1/4" or so

sorry for the bad pics, again.

so what is it? good? bad?

 

Looks like a pineapple sponge to me. They are good! Nice filter feeders.

 

+1 to the sponge. Should be fine.

 

Yep.

 

I concur! Scypha sponges are great to have!

 

cool!

any ideas as to why that one is so massive and the rest are tiny?

 

They are all sizes. Could be better flow containing more food. IDK. My bubble trap in my sump used to have 100's of them growing in it but they began to disappear and now I only see the occasional one here and there.

 

got it, cool. it freaked me out because ive never seen a picture of one so big

im not sure how they survived the cycle, but good for them!