On of my favorite tropes is the “kill am all” timeline. Where something changed, and the timeline is doomed. Cue all alternate versions of familiar characters dying horribly. And looking back, kid’s shows did this a lot. I remember Xialion Showdown had a big one for the finale, and in Teenage Mutant Ninja Turtles where Donny saw everybody he loved ripped apart. Though the Animorphs books had a version I still remember too.
Basically, it rips the heart apart while still keeping status who in the end.
It’s even better when everyone dies at once and it was caused by something that happened like 3 years ago that doomed the timeline like a character dying when they weren’t supposed to so they couldn’t do the thing to prevent the shit hitting the fan.