When Russian troops invaded his hometown in 2022, Ukrainian teenager Denys Kostev filmed TikTok videos cursing Vladimir Putin and praising Ukrainian courage. But a few months later, Kostev suddenly began appearing in Russian propaganda videos. WSJ’s Matthew Luxmoore spoke to the Ukrainian teenager about how he became part of the Kremlin's propaganda machine.  Further Reading: -A Ukrainian Teen’s Dark Transformation Into Russian Propaganda Star  Further Listening: -The Grim Story of a Russian Prisoner Turned Recruit  -Actors Recorded Videos for ‘Vladimir.’ It Turned Into Russian Propaganda.  Learn more about your ad choices. Visit megaphone.fm/adchoices