Can someone identify this toadstool?

[Shadysjl]

Found this little toadstool coral growing in an old shell. Does anyone know what type it is?

 

[wireefman]

if it was found in your tank, i would assume it is whatever kind you already have

 

[Potsy]

Leather corals are almost impossible to identify with any precision unless the spicules (uniquely shaped bits of carbonate that reinforce the coral's shape) are looked at under a microscope.