what is this mystery coral?

so its been in my dads tank for months upon months and I have no clue what it is!? Its pretty hardy cuz it makes it through anything!
I was thinking montipora at first but it is calcareous and very smooth. Light pink and encrusting with SUPER fast growth. It does have like literally 7 very small polyps throughout the whole entire coral tho...?

 

looks like a Porites to me Dingo
but I could be wrong

Steve

 

very possible steve... but do some types of porites not have polyps? this thing is like almost totally bare (kinda like coraline, except about 5X thicker and a much faster grower)

 

It could be a calcareous sponge.

 

chocolate chip cookie coral.

 

Looks like it's probably an encrusting gorgonian. When their polyps aren't extended, they look like a leather coral when their polyps aren't extended either.

 

encrusting gorgonian as in GSP??? i can 100% say its not any type of gsp

 

Green star polyps aren't gorgonians. Yes, they are an octocoral and they also encrust.....but there are a whole lot of other octocorals that encrust.

 

without the polyp remark it looks like an encrusting monti

 

i wonder if maybe its just some sort of ugly chalice???