The 1.30 update is here: Party Dungeons! Achievements! Arcade! Lava has requested a few things remain hidden for a week or two so everyone can get first time experience. NOTE: The Web version is not yet updated. There are a few lingering issues Lava needs to fix before that happens.
Baba Yaga Baby Eggs
Eventually you'll be able to turn these into a hatchable egg! Or maybe you already can! Or maybe you never will! Who knows what future content there may be!