Hi! Thanks for posting this~ I just joined (I'm the mystery nem owner) and thanks for the suggestion Joe~ it does look more like a Heteractis crispa than anything else I've seen, but what throws me off is that I keep reading sebae have pointy tapered tentacles... This one doesn't is that always a rule?
Traditionally yes they have long pointy tentacles. However I have had several that maintained very nubby and short tentacles that look very similar to those in the image.