On Beyond Zyzzlvaria

by Mike Selinker and Foggy Brume
Answer: CHAI

Each character is one of the last twenty letters after the letter Z in the Dr. Seuss classic On Beyond Zebra. In the book titles (all by Seuss under one name or another), the letters represent characteristics that define those words. However, those characteristics are obscured by the oobleck spill. The letters in the book's order, and their de-ooblecked characteristics:

The list of books by Dr. Seuss are represented this way. Bracketed words have been replaced by red question marks.

  1. Marvin K. Mooney [Will] You Please Go Now!
  2. You're Only Old Once!: A Book For [Obsolete] Children
  3. One Fish Two Fish [Red] Fish Blue Fish
  4. [Dr.] Seuss's Sleep Book
  5. Horton Hears a [Who]!
  6. [I] Am NOT Going to Get Up Today!
  7. [The] Butter Battle Book
  8. Green Eggs and [Ham]
  9. How [The] Grinch Stole Christmas!
  10. I Can [Read] with My Eyes Shut!
  11. Would You Rather Be [A] Bullfrog?
  12. Fox [In] Socks
  13. [Thidwick] the Big-Hearted Moose
  14. The Sneetches and Other [Stories]
  15. [Oh,] the Thinks You Can Think!
  16. Maybe You Should [Fly] a Jet! Maybe You Should Be a Vet!
  17. The Cat in the Hat Comes [Back]
  18. The Many Mice [Of] Mr. Brice
  19. I Can Lick 30 Tigers Today! and [Other] Stories
  20. The [King's] Stilts
  21. Mr. Brown Can Moo! Can You?: [Dr.] Seuss's Book of Wonderful Noises!
  22. And to Think That I Saw It [on] Mulberry Street
  23. Hooper Humperdink...? [Not] Him!
  24. Horton Hatches the [Egg]
  25. Because a Little Bug [Went] Ka-choo
  26. I Wish That [I] Had Duck Feet
  27. [The] Seven Lady Godivas
  28. The 500 [Hats] of Bartholomew Cubbins
  29. [My] Many Colored Days
  30. If I [Ran] the Zoo
  31. Did I [Ever] Tell You How Lucky You Are?
  32. Please Try to [Remember] the First of Octember!
  33. Hooray for Diffendoofer [Day]!
  34. Bartholomew and the [Oobleck]
  35. Scrambled [Eggs] Super!
  36. Oh [Say] Can You Say?

The first letters of these words spell WORD WITH TRAITS OF BOOK DONE WITH MR. ERDOES. Dr. Seuss wrote the book Come Over to My House with Richard Erdoes doing the artwork. The words in the title of the book would be represented by GLIKK (Come starts with C), THNAD (Come, to and House end with vowels), FLOOB (My ends with an "eye" sound), YEKK (House contains an H), and HI (Come and Over are four letters long). The only four-letter word starting with C, containing H, ending in a vowel, and ending with an "eye" sound is CHAI.