Stinkbug. This is known around here as the “hato-maku-mushi” or “heart-mark-bug” or kamemushi / stinkbug. There’s this girl I know, Tama-o-chan. She’s three years old and one day, she sees this stinkbug and is fascinated by the yellow heart on its back. She says “it’s so cute” (kawaii) and then picked it up and fiddled with it admiring it. Then she smells it like it’s a flower saying “beautiful” – and then the expression on her face changes to one of disgust “kusai” which means “it stinks”!
Here’s another stinkbug, a red beautiful one. If you look closely, you can see the black shiny “heart” marking on its back too.