Biolume Egg
Creature — Serpent Egg
Defender
When this creature enters, scry 2.
When you sacrifice this creature, return it to the battlefield transformed under its owner's control at the beginning of the next end step.
Serpents leave their eggs in the cold and inky depths...
Biolume Serpent
Creature — SerpentSacrifice two Islands: This creature can't be blocked this turn.
...knowing their hatchlings are more fearsome than anything else that might come along.
Filip Burburan
Rulings
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.
(wotc • 2021-11-19)
You can't sacrifice Biolume Egg unless another effect allows you to.
(wotc • 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.
(wotc • 2021-11-19)
Rulings
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.
(wotc • 2021-11-19)
You can't sacrifice Biolume Egg unless another effect allows you to.
(wotc • 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.
(wotc • 2021-11-19)