I agree with this. Physogyra lichtensteini is a species of bubble coral that looks like the coral in your pictures when it deflates and feeds. The bubble coral pictures posted by sqcube4me belong to the genus Plerogyra. This illustrates the problem with corals being sold by common name, as 2 different genera in this case are known as "bubble" corals. Other corals are often sold by genus, like Favia, Platygyra, etc.
I have that same one. It is a pearl bubble coral. They have an irregular polyp shape. Some are very oddly shaped. No two are the same. Mine deflates at times and other timed will puff out more than twice its size. Also sends out long sweepers.