Incarcifors is a Transforming spell that transfigures an object into a suitable prison for a nearby creature, allowing it to capture or imprison the victim.
Etymology
The prefix "incarci-" probably comes from the English "To incarcerate" and the suffix "-fors" (often used in transfiguration spells) is Latin for "chance, luck, fortune", though it may also come from "forma" (or simply English form) meaning form. Therefore, the full meaning of Incarcifors may be thought of as "change [so as] to incarcerate.