In the song "Paper Mario: The Thousand Year Door - Doopliss," Doopliss, a villain, has taken on the appearance of Mario and is trying to deceive his friends. The lyrics express the deception and the struggle to uncover the truth. The friends, including Koops, Flurrie, Goombella, and Baby Yoshi, stand together to fight against Doopliss and help Mario reclaim his true identity. They see through the villain's disguise and work together to defeat him. The song captures the themes of loyalty, friendship, and the fight for justice. The lyrics also showcase the humorous and playful nature of the Paper Mario video game series.