Dr. D. Capitator (Before you ask: Yes, this 'bot is not in RoboGauntlet. However, I simply have to vote for it because... well, It was awesome! Possibly one of my favourite robots, but the cheatbot2 usage unfortunately killed it. An image of the robot is below.)
But then again, we got Short Stack out of its rejection, so I'm not too sure what to think.
However, my
actual vote on the unluckiest robot goes to
Sliceberg-C, mainly because it was a good robot that only just failed to get into the tournament by the tiniest of margins, and the rumble progress and gauntlet grudge wasn't much better for it, sadly.