mare's nest

noun2

1. •
   (figurative) A confused or complicated situation; a muddle.

   • Though Chancellor Maupeou had supported the idea of a trial [...], the legal proceedings developed into a mare's nest of accusations and counter-accusations. — 2002
2. •
   (figurative) A great discovery which turns out to be illusory; especially, a hoax.

   • Why dost thou laugh? What Mares nest hast thou found? — 1620