The Cactuar is a character originally from the Final Fantasy series, a series from which many Kingdom Hearts characters originate. It is a living cactus known for its speed and prickly nature. In Kingdom Hearts 3, it appears (as shown in the screenshot attached) in the form of a giant stack of boxes that the player must photograph!
I believe that this would make a great Lego set because it is cute and is something that is not currently available! I would absolutely love it if some of the cute FF/Kingdom Hearts characters or objects made it into Lego sets! I believe that there is a large market for them!