Ok going through sprungs invert and coral books i've come up with 4 contenders
Contender one is a form of anemonia which is a subset of anemones. I say that because of the tip of said specimen. I personally don't think its that
The next three are corals
1) Cladocrora which i also don't think it is.
2)Diploastrea which is possible but i can't see the base
3)Duncanopsammia which i really think it is. Similar to tubastrea but different color and in need of light.
The key is does it have a stuctured base like the tubastrea? Those are my guesses.
EDIT: if i had time i'd go through bornemans corals book but i don't sorry