Donut opens a temporary hole beneath herself to escape a snare, then closes it around Cici's neck.
At the moment Cici lunges, Donut casts Hole under her feet. The spell removes the trapped floor section and therefore breaks the ninety-second snare, allowing invisible Donut to fall safely to the ground below.
Cici sticks her head through the opening while searching for the cat. Donut dismisses the spell, restoring the floor boundary and cleanly severing the dog's neck.
A round magical opening cut cleanly through a wooden treehouse floor.
Hole functions as both escape utility and an exceptionally lethal environmental attack.
Also appears in books you've already read — spoiler-safe to their endings: