24-year-old musician and mother-to-be [Ashlee Simpson] stopped in with her mom at art gallery and children’s bookstore Every Picture Tells a Story in Santa Monica, Calif. on Saturday and bought a print from The Nightmare Before Christmas.

Rocker hubby Pete Wentz has already finished several songs for a new album he is writing for his forthcoming child.  “Yeah!  I’ve got a version of ‘Baa Baa Black Sheep,’ done like, in this revved-up style, and of course I had to do a cover of ‘Enter Sandman.’

“I’ve been working on a new song called ‘Clown Parade,’ and just a lot of other things, you know, that babies like.  There’s one about how you never know what’s in the closet at night, one about running away from the hungry dinosaur—that kind of kid stuff.

“And after I finished reading ‘The Expectant Father,’ I started a three-song cycle about barfing.  The first one is about how Ash would hurl at night for like, weeks in a row—it was mad gross.  Then there’s a song about spit-up, which Ash says is going to be ‘my area’ to deal with once the baby comes.  And the third one is about my future reaction when the baby turns thirteen and I find out that she’s wearing a lace thong.  I’m really not looking forward to that.”

Wentz also elaborated on other details about the decor of the new baby’s room.  “Ashlee wanted to have the walls painted in a music theme, but also we wanted to make references to Halloween, since that’s when the baby’s due.  So I hired a designer and surprised her with the nursery’s new look.”

When asked about the design, Simpson rolled her eyes.  “Basses aren’t the only instrument in the world, you know.  And just because some of them are being played by black cats and witches doesn’t mean it fits in with my theme.  God, Pete, I leave you alone in the house for one weekend.”

“I have to run.  Mom and I are going shopping for more baby-appropriate decorations.”

Tags: entertainment, pete wentz, inappropriate baby decor, baby, halloween, ashlee simpson, frightening small children