Media being lost against the creator's wishes

I mean, it was ultimately a harmless dumb prank.

The directors of the Batgirl movie were against the deletion and shelving of it, and tried to get footage of the movie for themselves (but were unable to access it).

Idk if this counts, but the 1990 Tokyo Toy Show prototype for Sonic The Hedgehog was originally going to be included as a bonus in Sonic Mega Collection, but Sega apparently lost the ROM for it, which means that the prototype is most likely lost forever.

I made a post on this story recently, but the youtuber Oddheader wants his lost Mythica.com videos found. Since Mythica is a long-gone website, there was no choice in personally saving those videos, especially in the era prior to internet preservation becoming a more widespread concern.

The Sonic 1 TTS build is a Good Example of this, Yuji Naka wanted this to be included in Sonic Mega Collection but he couldn't find the ROM at all.

Ah man, I just got here in time before it gets moved. For my suggestion, I say Baby Blues' second season falls between the "media being lost against the creator's wishes". Warner Bros nor the creator of the comics refused to release what material was made for season 2, assuming it didn't get destroyed by WB. I have starting to fall in the newspaper comic strip rabbit hole recently, with Baby Blues being one that sticks it together when it comes to looking up comics on my phone. I'm always interested of how The WB didn't treat their later primetime cartoons (Baby Blues, Mission Hill, and The Oblongs) well compared to their other primetime series, Pinky and the Brain and The New Batman Adventure. And even then, both are also on Kids WB. And while Adult Swim eventually saved all three at once, only the latter two fully completed their one and done seasons, while Baby Blues, being the only series that had a second season ordered, ended up with the only season aired.