Banish to the Shadow Realm

A simple card with what looks to be a swirling void on the back, the front illustrates a person distorted and peeling from reality. 

This card, when thrown at a creature, banishes a singular creature within range (60 ft) to the Shadow Realm. The creature must make a Wisdom Saving Throw (DC 18) every minute they last in the Shadow Realm. At the same time, they take 1d6 psychic damage every minute. If they succeed the Wisdom save they escape the realm and re-appear where they were banished.