What is the fine-grained topic of the following text: “Waste It On Me” was launched alongside a colourful lyric music video, which options the imagery initially teased in a mysterious billboard in Los Angeles that excited BTS’ fandom ARMY and prompted “The Great BTS Billboard Hunt” hashtag as followers tried to determine what the signage was hinting. Only return the topic.
Release and fan response to BTS's song "Waste It On Me"