Childish Gambino stunned a bunch of teenagers in the Windy City on Monday when he gave a surprise performance of his #1 hit "This Is America" at Chance the Rapper's Open Mike Chicago. Consequence of Sound notes that Monday's event was the 30th Open Mike hosted by Chance and his SocialWorks charity. The free performance took place at the Harold Washington Library Center and was open to all kids with school ID. "My next guest needs no introduction,” Chance told the crowd before Gambino (a.k.a. Donald Glover) came out. “So let’s try it.” Video from the event shows kids rushing the stage as they recognized the opening notes of Gambino's platinum-selling song.