There is an empty square to the right of the Pokemon Center in Tapu Village, Ultra Moon. Is it an event or something? I brought my 4 Tapu to there but nothing happened. I don't think they made that thing just for fun/decoration :|
It's not meant for anything.
It's just there for "decoration".
Source: SM and USUM have been out for quite a long time for there to not be anything about that spot.