This page uses data from the Miitopia Param Info spreadsheet, compiled by PibPasquale, Kobazco, and UglyFrenchFry.
Frog Juice is a drink inside an orange bottle with a brown frog face on the bottom half. The bottle has a cork/bottle-stopper placed in the top and some purple string tied around the middle. There is ultimately no correlation between this Grub and the enemies that drop it save the basic frog element.