noun
( plural mare's nests or mares' nests )
1. : a hoax or fraud or some other nonexistent or illusory thing that seems at first to be very wonderful and full of promise but that ultimately brings ridicule on those deceived by it
creating a neat little mare's nest in English dramatic history — R.S.Loomis
spent his whole life looking for what was actually a mare's nest
2. : a place, condition, or situation of great untidiness, disorder, or confusion
the hold of the ship was a mare's nest
had made a mare's nest of the administration