2021-11-19 : If a permanent that isn't a double-faced card becomes a copy of Biolume Egg and then is sacrificed, that card can't be returned to the battlefield transformed. It will remain in the graveyard.

2021-11-19 : You can't sacrifice Biolume Egg unless another effect allows you to.

2021-11-19 : You may sacrifice any two lands with the subtype Island to activate Biolume Serpent's ability, even if they aren't basic or aren't named Island.