Ethereal Librarian Egg

Ethereal Librarian Egg
Group Basket
Sub Group Spring Eggs
Tradeable No
Refundable No
Limited Edition No
Random Items from Ethereal Librarian Egg

Opening this gives you one or more of the following: Details in the MHWiki link below

Description
Thankfully, this egg is fully corporeal, though the mouse guarding it is not.
Mousehunt Wiki page