Ultrasonic chef’s knife

3 years ago I wrote a cyberpunk novel for NaNoWriMo. In it, one of the hoodlums was waving around a “compu-knife”. A knife that you have to pair to a smartphone app over Bluetooth, or it won’t work.

All together now: Cyberpunk was meant to be a warning, not just an aesthetic.

(I know, I know, the article doesn’t say the knife needs to be paired to an app. I feel lucky about guessing it does though)