Me too!
While browsing on e-hentai, found an other intresting idea not unalike the one of Berty's watch: a product that temporary kill a persone. The one that take it is dead but only for a limited amount of time, and once this time is over ther persone will come back to live no matter what happened to his/her body while he/she was dead.
See it here : https://e-hentai.org/g/973540/16b7ae3ece/