The performer shows a video that displays various card values. A spectator mentally selects one, then mentally tears off a corner of the selected card, and that card corner appears in the phone.
To perform this effect all you need is a phone that can play back an MP4 video. This is not an app and can therefore be performed on pretty much any modern smart phone. Please note that in most cases the card corner will appear in the video that is played back. In some cases the card corner will materialize as actual card corner.
1st edition 2019, length 7:41