On The Serpent album theres a song called Avalanche, for those who dont know, Avalanche is name of terrorists or rebels in FF VII, in which their mission was to take down one of Shinra's reactors, in hopes of taking down Shrina. The song goes on about "the ultimate weapon", "jenova", "stream of life" etc. You'll know this buy either watching the "FF VII Advent Children" film or just playing the game. Im not sure if its a real egg, maybe its just a tribute.