Judging by the name and the description of the achievement, I imagine that I'm supposed to get a weight of 666 on the scale at the carnival.
I've tried some combinations of characters, and I've seen that each one of them has his own weight. I've also seen that you need to carry some items on the scale, otherwise the weight will be too low.
Is there only one specific combination of character that will get me the achievement or I can simply play with the items and get it with any trio? Are there specific items too? I've tried taking the barbell and the wrench on the scale, but I'm still missing some weight.