Branching hammer. Same family as Frogspawn and Torch (all are Euphyllia sp. and are compatible with one another).
They will eat meaty foods if they catch them - they have many mouths in the tissue close to the skeleton.
It's hard to tell from the photo if it's just glare or if the specimen is bleached. Try googling for branching hammer coral and see if what you find resembles the colouration of yours - it shouldn't be transparent or 'white', but it does come in a number of different morphs, some are fluorscent, some are not.
Jenn