I'm with the naysayers...
When I saw that Bison, I was like WOW!!!! NIB!!!! then started wondering what the "catch" was....
Sure enough....busted/dissolved housing. No thanks! Not only does that defeat the purpose of being NIB, but where the heck are you going to find new housing for it? I mean I guess if you've got a parts machine laying around it'd be a good buy, but still not NIB anymore. If you don't have the parts to fix it, kiss it goodbye. The auction even claims that the plastic is very fragile and will break if you touch it!
If you read further, it says it looks like some oil dripped out of the motor or rear axle section......possibly a blown seal or something? It looks like it's got a transmission or something. I don't know anything about Bison themselves, but the warning signs on that one are pretty clear!