If I'm not wrong, I think this komarisa got addicted to sakura petals and refuses to eat anything else, when told there are no more, it cried still demanding the petals while throwing it's shit all over the house.
The parents probably throw it away in the park's sand box where it deems it's surrounded by prtals and proceed to eat the sand around it.
After fully awake, it refuses to acknowledge that it was cast away and most likely go nuts, eating the sand and scaring a stray alice family, the picture above shows it's poopoo are hardened because it keep eating sands.