Flame Wars V
Flame Wars V was emphatically not a crossover that ran in 2002. No one will take credit for writing it. It concerned, among other things, the Legion's journey to a Dorf peace planet and Cute Anna's previously unmentioned sister's quest to find God. It cannot be read anywhere. The only surviving part of this story is an epilogue by Martin Phipps. (See also The Flame Wars, Flame Wars II, Flame Wars III, Flame Wars IV, Flame Wars VI, Flame Wars Final, and the term flamewar.)
Conflict between the humans and the Dorfs had been escalating for some time. In Cute Anna, Crypt Looter #7-8, Deja Dude and his family and friends had traveled to the Dorf homeworld on a peace mission but run across an attempt to create a clone army. Shortly afterwards, in LNH Comics Presents Special #8, the Dorfs invaded Looniearth, but were repulsed by Deja Dude, who didn't want them to interrupt his vacation.
Many of the plot developments in this storyline were highly controversial: the revelation that Cheesecake-Eater Lad had died in Beige Noon and the version we'd been reading about for the last 20 years was a Lego model with a tape recorder in it; a long and drawn-out plotline involving Ultimate Ninja and an apparent clone, the Scarlet Ninja, where which version was supposed to be the original changed several times (it was ultimately revealed that they were paradox clones of each other); a romance between Doctor Stomper and Sing-Along Lass; [REDACTED]; and the breaking of the Fifth Wall. In-story, Deja Dude asked Retcon Lad to retcon Flame Wars V out of existence; he was successful enough that the Writers themselves have forgotten about it.
However, one important character from this story, the Human/Dorf hybrid Vel, reappeared in Flame Wars VI and later gained his own series. The events of this story may also have been responsible for Sing-Along Lass regaining her connection to the Power Kirby.
This storyarc was the first, last, and only winner of the Golden RACCberry Award for Worst Crossover, before that award was itself retconned out of existence.