Does anyone know what is this

[HeriPadi]

On Apr 28, 2018 I brought 2 Candy Cane Coral Frag at my local pet store. I realize that of one of my Candy Cane have some thing at the bottom. Can anyone know what this white thing is.

 

[Maritimer]

Looks like a sponge - a filter-feeder, harmless at worst. Many consider them beneficial.

~Bruce

 

[evolved]

Pineapple sponge

 

[KJ]

Ball sponge.