ThunderCats (1985)

S1E36 The Evil Harp of Charr-Nin

Wilykit and Kat stumble upon an ancient harp that houses a genie named Charr-Nin. Mumm-Ra confronts the genie, promising him freedom from his confinement within the harp if he agrees to eliminate the Thundercats. Naively, Charr-Nin accepts the deal and starts capturing the Thundercats one after another. However, Mumm-Ra's true intentions soon unfold as he betrays Charr-Nin. Amid their heated confrontation, the Thundercats find a way to break free, leaving Mumm-Ra and Charr-Nin to clash in a fierce battle deep underground.