The unaired pilot of Hi Hi Puffy AmiYumi is exactly as the title implies; it was the pilot for the show but never aired.
When Sam Register decided to pitch an idea of Puffy AmiYumi having their own TV series, Renegade Animation made a test pilot in 2003 that was (unfortunately) only sent to Cartoon Network in hopes of them to greenlit that said idea. Numerous differences include Ami and Yumi looking different than their final cartoon counterparts, having different voice actresses and having slightly different personalities, Kaz being absent, Ami in some shots having ponytails instead of buns, Yumi sometimes having sunglasses on her hair in some shots and the animation being jerky at times.
The only footage of the pilot is the promo (which can also be watched on this article) found by Tumblr user retal4, which can be found in some Teen Titans DVDs and VHS tapes. There's also screenshots of the promo as well, also found by Tumblr user retal4.
According to puffycrew (Hi Hi Puffy AmiYumi's (now down) development blog) in the post "Some early stuff" by Scott O. Brien, from the second June 2006 archive of it in the Wayback Machine, the show was originally going to be about Puffy AmiYumi moving out from Japan to unintentionally discover the weirdness of America.
There were also concepts with Ami and Yumi being in different costumes in the pilot's art style. These were possibly later used or re-used in the third episode's third segment.
- Male taxi driver
- Massively big football players
- Blonde-haired man
- Dinosaur (which later reappeared in the 5th episode segment "In the Cards")
- Robot (which later reappeared in the 5th episode segment "In the Cards")