Glenn Danzig is well known as the lead singer of the heavy metal band, Danzig and former singer for the punk rock band, the Misfits. He appeared in the episode Cybernetic Ghost of Christmas Past From the Future (voicing himself) when he bought Carl's house for $1,000,000 in order to enjoy the spring of elf blood that erupted from his pool.
The sale also apparently included the Cybernetic Ghost as part of the deal, who fled to the Aqua Teens house some days later and asked them to hide him, complaining "He is so annoying, he is so frightening, and he doesn't wear a shirt!".