Blue's Big Costume Party is the 21st episode of Blue's Clues from Season 3.

Characters Present


Steve and Blue host a costume party.


  • Question: What could Magenta wear to the costume party?
  • Clues:
    • 1. Little Prints
    • 2. Whiskers
    • 3. The sound (Squeak-Squeak)
  • Wrong answers:
    • Rhinoceros costume
    • Cat costume
  • Answer: Mouse costume
  • Living room picture: Boo's Haunted house (also the skidoo location, same as What Is Blue Afraid Of?)


  • This episode is a Halloween special.
  • This was surprisingly filmed before Blue's Big Pajama Party.
  • The term Oogla Boogla was previously mentioned in the Mailtime segment back in the Season One episode "Blue's Story Time".
  • Throughout this episode, Steve gets a spooky surprise whenever he opens his notebook.
  • In the Mailtime song, Blue does not join in the singing.
  • This is the first episode to use the "A clue! A clue!", "Right there!", "Notebook!", "Thinking Chair!" and "No!" phrases.
  • This is the last episode to use the "Right there!" phrase from Math!.
  • This is the only Season 3 episode that Steve gives a wrong guess.
    • This is also the only time where Steve gives more than one wrong guess, and the only time when he observes each of the clues individually.
  • This is the third time Steve gets the mail at the end.
  • This is Boo's second and final appearance on the show.
  • The felt board picture shows Freddy and Fifi wearing their alien and astronaut costumes from "Magenta Comes Over".
  • This is the 3rd time Blue was peeked into the leaves from "Blue's Big Mystery" and "Thankful".
  • This is the last episode where Steve skidoo’s into the Living Room Picture Frame.
  • This is the only time "Hi, Steve!" is never said in the beginning of the letter.


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Blue's Big Costume Party

Blue's Big Costume Party

Blue's Clues Season 3
Blue's Big Treasure Hunt | Art Appreciation | Weight and Balance | What's That Sound? | Animal Behavior! | Blue's Big Pajama Party | Draw Along with Blue | Hide and Seek | Thankful | Blue's Big Holiday | Pool Party | Anatomy | Signs | Nature | Geography | Occupations | Blue's Big Mystery | Periwinkle Misses His Friend | Blue's Big Musical | What's So Funny? | Blue's Big Costume Party | Inventions | Blue's Play | Prehistoric Blue | The Wrong Shirt | Words | Shy | Magenta Gets Glasses | Environments | Stormy Weather | Blue's Collection | Café Blue
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