The Wild Thornberrys (found pilot of Nickelodeon animated series; 1998)
The Wild Thornberrys was a Nickelodeon animated series created by Klasky Csupo that aired between September 1st 1998 and June 11th 2004, with occasional reruns in following years. The series' pilot aired on the same day that it premiered (and once more a month later during the "Big Help-a-Thon 5" event).
Plot
The episode involved the Thornberrys trying to acquire footage of an elusive black rhino in Kenya in order to save their TV show from losing funding. Meanwhile, a pair of poachers catches word of this and wishes to capture the rhino for its horn. By the end, the poachers fail and the Thornberrys get their footage.
Availability
For unknown reasons, the pilot was not included on any DVD releases of The Wild Thornberrys, and as a result, it eventually faded into obscurity and became lost.
However, on May 11th 2013, Youtuber "jeffdadude87" uploaded a recording of the pilot during its "Big Help-a-Thon 5" broadcast. While this particular video is no longer available, another user reuploaded it, meaning the pilot is still available for viewing.