These Sclerohytum from the waters around Palau first appeared in the local trade in the early 2000's. Reef legend Greg Hiller called them "Screaming Green Tree Coral", but they are truly much closer to yellow than traditional "Green Tree Coral" of the same genus. 
(2nd pic is mother)
Disc is approx. 1.5" 
The specimen in the image is the exact one you’ll receive!