Mr. Mxyzptlk turns Jimmy Olsen into a turtle. This pays tribute to Turtle Boy, an altar-ego Olsen carried in the comics.
Superman is seen shaving with his heat vision. This comes from the post-Crisis comics idea, written by John Byrne, based on the fact that Superman's skin (hair and all) is too strong for conventional blades to work.
Mr. Mxyzptlk calling out "McGurk" is a tribute to the very first comic story of Mr. Mxyzptlk.
The writers wanted Mr. Mxyzptlk to appear in Justice League (2001), but could not manage to get an episode to do so. This was because the producers felt him too much of a comic figure (even though he was nearly omnipotent) for the show.
The comics in the newspaper are:
-"Mxyzptlk" by Jerry Siegel and Joe Schuster (the original creators of the Superman comic)
- "Dini the Meany" by Bill Wernissu, based on Bill Watterson's "Calvin and Hobbes" (but named for series writer Paul Dini )
- "Gleen" by Broken English, which mimics Charles M. Schulz's "Peanuts"
- "Dan Danger", a parody of Dick Tracy
- and Zub Street, which imitates Mell Lazarus's "Momma."