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"Blue's Big Costume Party" is the 18th 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. A Squeak Sound
  • Wrong Answers:
    • A Rhinoceros Costume
    • A Cat Costume
  • Answer: Mouse costume
  • Living room picture: Boo's Haunted house (also the skidoo location, same as What Is Blue Afraid Of?)
  • Felt frame picture: Felt Mouse Footprints (as a clue) then Felt Friends wearing outer space costumes on


  • Steve: What is this thing you call clue
  • Steve: Blue Pawprint An Object Spotted.
  • Steve: Oh Look!, it's Boo!!
  • Boo: Ahh!!
  • Steve: Ahhhh!!!
  • Slippery: Yep it's Me, See!!
  • Oogla Boogla: Well there you are. I've sent Boo to get you.
  • Oogla Boogla: I've made some Oogla Boogla treats for Blue's party. These are for you!


  • 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".
  • Victoria Pontecorvo and Madeleine Steinberg are friends of Steve in this episode. Pontecorvo will be the voice of Blue in Blue's Room and Madeleine is related to Amy Steinberg, an Executive Assistant. The list of Steve's Friends was previously used in Periwinkle Misses His Friend.
  • 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 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 original show.
  • This episode simmilar than Blue's Big Costume Parade.
  • In UK version after sing So Long Song Kevin was teleport from outerspace. but steve does not do it.
  • The felt board picture shows Freddy and Fifi wearing their alien and astronaut costumes (respectively) 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 second last episode of season 3 were Steve ended The Mailtime Song on the right side of the screen.
  • This is the last episode where Steve skidoos into the Living Room Picture Frame and into something off the ground.
  • This is the only time "Hi, Steve!" is never said at the beginning of the letter.
  • This is the first episode where Shovel & Pail appear mirrored in the credits.


  • Blue had her fish costume during The So Long Song. However, when she barks and waves Goodbye to the viewers as it zooms out of the house, she is seen without her costume (because the producers recycled the animation) and it is unknown how she got it off in such a fast time.


Watch Episode

This episode is available for streaming on Paramount Global's video streaming service Paramount+.
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