I was wondering why my eclipse rear end of the car wants wonder violently on slick roads??? The car seems like it is fish tailing, while I am constantly fighting it to keep it from looosing control??? It also pulls to the left pretty hard and the rear drivers tire only is severely cupped. Wondering what it could be ?????

toe is fuked on one side of rear.
get the car aligned.

I agree, have the alignment checked, there is probably something bent back there.