Character Analysis
Eddie Monster
Eddie is Frank's failed experiment, Columbia's ex, and a really good singer…not just for a dead guy, but for live guys too. In the brief moment we see Eddie, he seems sweet and genuine. (No wonder Frank kills him. Those two words aren't in Frank's vocabulary.)
FRANK: One from the vaults. Oh baby! Don't be upset. It was a mercy killing. He had a certain naive charm, but no muscle.
Even though Eddie is barely on screen for more than five minutes, critic Emily Asher-Perrin sees him as an allegory for the death of old-school rock 'n' roll and the rise of glam rock in the 1970's. (Source)
There is no room for Eddie's square sincerity in a genre that wants its performers to be larger than life, plastered with makeup, and dressed up in crazy clothes.
After being killed with a pickax, Eddie's still mined for a bit more drama. Frank literally serves Eddie for dinner, using him as a tool to get back at everyone. Dr. Scott is Eddie's uncle, and Columbia is his ex. They're extra horrified by Eddie's fate.
Before his body is revealed, though, the characters sing about him being a "no-good kid" and a "low down cheap little punk."
NARRATOR: He was a low down cheap little punk!
SCOTT: Taking everyone for a ride.
ALL: When Eddie said he didn't like his Teddy, you knew he was a no-good kid. But when he threatened your life with a switch-blade knife…
FRANK: What a guy!
JANET: Makes you cry.
DR. SCOTT: And I did.
Just as Janet falls into the virgin/whore dichotomy, Eddie's your stereotypical bad boy. He was a troublesome teenager, but he was also idolized by others for being a tough guy with the same qualities his parents dislike seeing in him. Chicks dig a bad guy…but this bad guy's one they'd actually have to dig up. Ew.