Dexter's Laboratory (other lost aspects)

Rude Removal isn't the only Dexter's Lab gem to have been famously lost. Other gems of Dexter's Lab, including one Dial M for Monkey episode, are now lost as well.

There are two student films that the show creator Genndy Tartakovsky directed and animated at CalArts: The former which became the basis for Dexter's Laboratory, and the latter is unknown. The two films are considered lost and have not resurfaced online.

The original What-a-Cartoon! airings of the two pilots, "Changes" and "The Big Sister", the original TNT airing of "Old Man Dexter", and the original TBS airing of the episode "Dimwit Dexter" (originally titled "Dumb Like DeeDee"), all of which include different opening and closing credits, are lost, not taped off the networks, and have not resurfaced since.

One episode of Dial M for Monkey, "Barbequor", was pulled from rotation by Cartoon Network in 2004 due to the copyright holders of Marvel Comics' Silver Surfer objecting to their use of the character Silver Spooner and filed a lawsuit against the network for copyright infringement. As a result, post-2003 reruns of the show as well digital retailer releases from iTunes and Netflix as well as the Cartoon Network: Hall of Fame DVD release of Dexter's Lab: The Complete First Season deleted the episode and replaced it with a Season 2 episode "Dexter's Lab: A Story". However, it was released on the Dexter's Lab Season 1 DVD in Region 4 and was also uploaded to YouTube via user Cameran Barkley in 2012.

And finally, there is a noteworthy Dexter's Lab crossover with the most popular Cartoon Network series The Powerpuff Girls that has never been made into a television special. It has only canonically happened even though it never aired on television: Two IDW comic strips, Powerpuff Girls: Super Smash-Up! and Cartoon Network: Super Secret Crisis War! featured a Powerpuff Girls crossover with Dexter's Lab, Cow and Chicken, Courage the Cowardly Dog, Ed, Edd n Eddy and other Cartoon Network shows. Characters from the two shows also cameo appeared in some other Cartoon Network crossover episodes and also in the games, and only a handful of characters from Dexter's Lab (minus DeeDee, Mandark, Mom, Dad, and Monkey, whose cameos as toys also don't count) either cameoed or fully appeared in some episodes of The Powerpuff Girls. So far besides all this, Dexter's Lab and The Powerpuff Girls have no official crossover episodes in the actual show and Cartoon Network has no plans of considering the crossover as a full-length television film, probably because Dexter's Lab wasn't all that popular.