A riddle about rap music is:

Q: What is a mummy’s favorite type of music?
A: Wrap.

The “wrap music” joke has been cited in print since at least 1988.


5 November 1988, Palm Beach (FL) Post, “Cryptoquip,” pg. 11D, col. 5:
Yesterday’s Cryptoquip: WEIRD, APT SOUND HEARD IN LOCAL MUSEUM, NEAR THE MUMMIES. WRAP MUSIC.

Google Books
Hide-and-Go-Shriek Monster Riddles
By Meyer Seltzer
Niles, IL: A. Whitman
1990
Pg. ?:
What did they listen to at the mummy party?
Wrap music.

6 January 1992, Kokomo (IN) Tribune, “A Little Bit of Humor,” The Bubble Gum Rapper, pg. 18, col. 6:
Lakeshia: What king of music do mummies listen to?
Tyrone: Wrap music.

Google Groups: soc.culture.filipino
HAPPY HALLOWEEN
Gorgeous
10/22/96
(...)
Q. What kind of music do mummies listen to?
A. Wrap music.

30 June 1997, Detroit (MI) Free Press, “Yak Yuks,” pg. 2C, col. 1:
What is a mummy’s favorite kind of music?
Wrap music.
From Samantha Mitchell, 8, Hazel Park.

31 March 1999, Los Angeles (CA) Times, “The Kids’ Reading Room; Pint-Sized Punch Lines,” pg. 7:
What is a mummy’s favorite music? Wrap music. (Amy, 10, Fountain Valley, Cox Elementary)

Google Groups: alt.humor
Looking for halloween material
fmhlaw
9/29/00
What type of monster really loves dance music?
The boogieman!

What’s a mummy’s favorite music?
Wrap Music!

Google Groups: aus.jokes
Mummies & Deadies
Mr Funny Bone International
10/30/01
(...)
What two types of music do mummies like best?
Rag time and Wrap.

Google Books
The Everything Kids’ Joke Book:
Side-Splitting, Rib-Tickling Fun
By Michael Dahl
Avon, MA: Adams Media
2001
Pg. 3:
What is the Mummy’s favorite music?
Wrap.

Twitter
Brette
‏@brettegarner
What’s a mummy’s favorite kind of music?  wRAP!!  (we’re gonna party like it’s 1999...BC!) http://twitpic.com/il7r
8:00 AM - 28 Oct 2008

Twitter
Chris
‏@KintuLabs
What music do Mummy’s listens to? .................................................................Wrap Music Happy Halloween everybody!
7:56 AM - 31 Oct 2008

Google Books
101 Amazing Spooky Jokes
By Jack Goldstein
Andrews UK Limited
2013
Pg. ?:
What is a Mummy’s favorite type of music?
Wrap!

Google Books
Funny Mummy Jokes For Kids
By Peter Crumpton
PeteyRF Creative
2015
Pg. ?:
What kind of music do mummies like most?
Wrap music!

Twitter
Celebrations.com
‏@celebrations
Q: What kind of music do mummies like most?
A: Wrap music!
Check out these #Mummy #Cookie #Pops in M&Ms Graveyard: http://ow.ly/N5we305ybRq
6:01 PM - 26 Oct 2016