Originally, Judge didn't really want to voice Beavis, since all he really had for Beavis was the laugh. Beavis wound up being one of his favorite voices to do on the show.
If Daria had not been a ratings and critical success from episode one, Glenn Eichler has stated that MTV would have most likely have forced him to incorporate Beavis and Butt-Head into the show to boost ratings.
Tom Anderson was originally going to have a spin-off series on FOX, but legal issues kept Judge from using the character outside of MTV and Viacom, which is why Judge recreated Tom Anderson as Hank Hill for King of the Hill. Anderson was also going to be Hank's Shell-Shocked Veteran father, but, once again, legal issues kept Judge from using the character outside of MTV and Viacom, which is why Cotton Hill was created.
The relaunched series was initially going to have Beavis and Butt-Head as adults. For some reason, it was decided to keep them as teenagers when it finally went into production. After Judge decided to keep them as teenagers, they were originally going to have been frozen for a decade, then brought back and made to seehow life has changed since the 1990s. He would sort of revisit this concept with the 2022 revival, which seems to have quietly retconned out the 2011 revival as a result.
Atari had plans to make an Arcade Beat Em Up based on the show, which even made it to the play testing stage. However, it tested very poorly and Atari quietly cancelled it. About 10 prototypes were known to exist.
The episode Scratch N Win was originally going to end with Beavis and Butt-head crashing their riding mower, causing it to set on fire. Proof of the lost ending's existence is shown in some merchandise detailed in this video. It can be assumed the reason this ending was cut since the episode first aired not long after the infamous fire controversy.
The 2022 episode "The Special One" was originally meant to be a musical.
Warner Bros. originally wanted to do a live-action movie that would double as a vehicle for David Spade and either Adam Sandler or Chris Farley as the title character (in hindsight, a Beavis and Butt-Head film staring the "Bad Boys of SNL" would have been the single most '90s thing ever). Judge and everyone else at MTV hated the idea and after Viacom's acquisition of Paramount Pictures in July 1994, Warner dropped out. Judge then convinced Paramount that doing the film as animation would be much cheaper and more rewarding for certain scenes.
The "virus" plot was originally about a virus that spreads and slowly turns people into Beavis and Butt-Head clones. Judge also pitched a joke concept of Beavis and Butt-Head eating lunch at Burger World for an hour and a half in real time.
A deleted scene involving the duo going to the National Archives and Beavis using the Declaration of Independence as toilet paper was cut before release; Judge mentioned on the DVD commentary it didn't test well with audiences. It wasn't included on said DVD, strangely; it was, however, aired after the film when it premiered on MTV in 1999.
During production, the 1996 election was going on, and they created an alternate take of the scene where Butt-Head encounters Chelsea Clinton, showing her packing her things to leave the White House; this was never used since Judge eventually realized Bob Dole wouldn't win against Bill Clinton.
According to Mike Judge, there was originally a scene where Van Dreissen encounters the duo in present-day Highland and due to them being gone for over twenty-years, doesn't recognize them.
. It can be assumed the reason this ending was cut since the episode first aired not long after the infamous fire controversy.