'HEY TAYO' and 'BILLY POCO' are singles released by ENHYPEN in collaboration with the South Korean children animation show, 'Tayo the Little Bus'. ENHYPEN released a remake of the animation's opening song titled 'HEY TAYO' on July 29th 2021, followed by 'BILLY POCO' which was released on August 11th, 2021. 'BILLY POCO' is a newly made track which introduces the four construction (heavy) vehicles in the show, named Billy, Poco, Max, and Chris.