Shrinking scene starts near page 213, 2 girls and 2 boys basically have the Alice In Wonderland "Drink Me" (shrinking potion) / "Eat Me" (growing cakes), they use it to get tiny (bug-sized), they explore some vents and get almost eaten by a mouse. They all manage to get back to normal size quickly enough, except one girl who loses her growing cake in the chaos and end up lost in the grass with no way of getting back to normal size. She almost gets crushed / mistaken for a cockroach and poisoned by bug spray, until her friends finally find her the next morning.
https://archive.org/details/sistersgrim ... k/mode/2up

