Learn ‘Undo’ First
You find a box in the attic.
A magic wand rests in a case lined with red felt. A classic wand — black shaft, white cap, forearm’s length. Tapping something (or someone) with this wand while shouting “ka-ZAM!” will make that thing (or person) disappear. There is no obvious way to bring back anything which has been thus dematerialized.