Panic! at the Disco & a 'Stranger Things' Star Reunite On Stage: Watch

Panic! At the Disco fans were in for a fun surprise during last night's concert at Madison Square Garden, where the band brought Stranger Things star Noah Schnapp on stage. The buddies came together to sing along to "L.A. Devotee" off Panic!'s GRAMMY-nominated Death of a Bachelor album.

The crowd went wild as Schnapp adorably hopped around stage while performing the track alongside frontman Brendon Urie. The actor shared a photo from a few moments before he went on stage with the funny caption, "I look like I just saw the demogorgon." Schnapp was the main star in last September's twisted video for "L.A. Devotee", where he was inducted into an underground Los Angeles cult.