That happened to me once on a 10-Floor normal Scarescraper. I was playing to get all the bosses, when I find an empty tower with another player- 'staffie', I think it is. Not knowing what would happen, I entered the tower.
It was only a matter of time before he proved his uselessness. It was floor 2, and we were each going our respective ways on the floor. Without realising, he picked up a pumpkin. I took nothing of it and continued on, but soon enough, he starts to call for help. I tried to show him how to dislodge it. It was only after I accidentally got a bomb to hit him that it was dislodged. The next floor, he wandered an entire room with a key while I stood by a locked door yelling 'Hey!'. Finally, he opened it, but with a little bit of time remaining. On the boss floor, he then had the nerve to disconnect while I was low on HP and struggling.