"Sumbakkokjil" also known as "Hide and Seek" is an original song by Ho-ong-i featuring SeeU. Originally, it was uploaded to tvPot and Crecrew until two websites has been shutdown. Despite it's no official uploads, till' this day it became the most well known SeeU songs.
The story of this song is about a cursed girl chasing a boy in a violent game of hide and seek. It is hinted that the boy has done something wrong in the past and thus he is chased. In the end, he is caught and when the girl touches him she falls over, dead, and the boy is then cursed to chase a child who has done wrong and the cycle continues. It is unknown whether this girl is the first in the cycle or if she is just one of many and if there is more then one of these cursed children at a time. One theory says that this song is about a famous game and also a dark ritual from Japan and Korea called "Hide and Seek Alone". Another theory says that the girl is a yandere, and the boy, her lover, hates her.