It's a gravestone, because I thought that, after making her a trinket, I wanted to reuse the model. Trinkets are only used rarely, graves are used a lot more often and are more visible, and this Unikitty model wouldn't work well as a hat/glasses/moustache :P.

Watched the lego movie twice so far, so I really like this GRAVESTONE? Why is unikitty a gravestone? (bubblegum,butterflies GRRR!)