I was just curious what the rarest achievement from a reasonably popular game on Giantbomb is? And by "reasonably popular" I'd say something that enough people have played so, something like 5,000+ copies sold at least? (Going on the Rayman Origins Scale here). I was going through my own achievements and realized completing 'Splosion Man on the hardest difficulty has only been achieved by roughly 180 people.
What're some of your most well deserved, hardest, and just generally annoying achievements you've achieved a "Rare" rating for here on Giantbomb?