Oh. My. Goodness. It seems as though a sandcastle Pocket Monster is coming to the upcoming 3DS title Pokemon Sun and Moon. In the upper corner of the below image, you can see the small Ghost/Ground type Pokemon called Sunabaa (スナバァ), which is a riff on the Japanese word for sandbox, sunaba (砂場).
— かに (@kani_club_) August 9, 2016
Sunabaa evolves into the Ghost/Ground type Pokemon called Shirodesuna (シロデスナ), which can literally mean "A Castle of Sand" or be a word play on the Japanese "城ですな" or "That's a castle." Note that the standard way to write sandcastle in Japanese is "suna no oshiro" (砂のお城).
— すー＠ロズレキラー (@sue_Scyther) August 9, 2016
These Pocket Monsters were apparently revealed in an upcoming issue of Japanese magazine Coro Coro Comic. It should get its official announcement shortly.
Pokemon Sun and Moon will be out on the 3DS this November.