What's the worst rumble you ever posted?
Maybe you didn't quite understand the differences in power scale between two different universes at the time. Maybe you didn't understand how the rules on this forum operate. Maybe you just didn't know enough about one of/both of the participants in your rumble.
For me, for example, when I first joined the previous forum back in 2003/4, I posted "Illyria Vs The Silver Surfer".
This was before Angel Season 6, so Illyria didn't even have her comic book feats (and that match would still be a stomp even if she did). I wanted to know if Amy Acker's TV portrayal of Illyria could take on the comic book Silver Surfer, because she was arguably the most powerful thing in the Buffyverse at the time, so - at least I thought - she MUST be able to hang with Marvel's big guns.
How wrong I was and how much I've learned here!
So what's yours?