It is difficult to determine the "worst" Kpop music video as this is subjective and dependent on individual tastes and preferences. However, there are certain music videos in the Kpop industry that have received criticism for various reasons.
One such music video is "Growl" by the Kpop group EXO. The music video received criticism for its use of CGI and special effects, with some viewers finding the effects to be poorly executed and detracting from the overall aesthetic of the video. Additionally, some fans and critics also took issue with the concept and choreography of the video, finding it to be unoriginal and lacking in creativity.
Another music video that received criticism is "I Am the Best" by the Kpop group 2NE1. The music video was criticized for its use of blackface, with some viewers and fans finding it to be culturally insensitive and inappropriate. The blackface controversy resulted in the video being removed from some platforms and edited in others.
It is worth noting that while these music videos received criticism, they were also commercially successful and remain popular among fans of the groups. The music industry is subjective and what may be considered a "worst" music video by one person may be highly regarded by another.
It is important to remember that music is a form of artistic expression and as such, opinions will vary. The opinions expressed in this answer are based on information from various sources and should not be taken as a definitive statement on the quality of the mentioned music videos.