Just in Mono Black alone I'd say Yawgmoth, Thran Physician is a better Sacrifice commander, and once you start adding additional colors there's Meren of Clan Nel Toth, Teysa Karlov, Marchesa, the Black Rose, Korvold, Fae-Cursed King
The name egg comes from the Odyssey cycle of eggs, like Darkwater Egg and Mossfire Egg
You get an incredible reanimation spell that can easily swing a game in your favor in the right deck
In other colours that might be a bit infrequent but green gets to six often and at good pace
You can make it grow by self-milling too, which is something GB decks have the tools for
I think this means were missing a big portion of the story and maybe even some potential solutions to the issue of counterfeits that could come from understanding the counterfeiters