If I control two different Essence of the Wild but they're not exactly the same, what do my creatures come into play as copies of? Do I get to choose?
Let's say that I have one Essence that's been mutated with Cloudpiercer, and another that's been mutated with any other creature like Sea-Dasher Octopus.
You get to choose. Essence of the Wild has a replacement effect that replaces how a creature would enter the battlefield so you as the affected objects controller get to choose the order they apply in. You apply one and then the second will overwrite it.
'If you control more than one Essence of the Wild, creatures you control will enter the battlefield as a copy of the one whose copy effect you apply last.'
...and it's in the rules:
614.1d Continuous effects that read (…) “[Objects] enter the battlefield . . .” are replacement effects.
616.1. If two or more replacement (…) effects are attempting to modify the way an event affects an object or player, the affected object’s controller (…) chooses one to apply (…)
Let's say that I have one Essence that's been mutated with Cloudpiercer, and another that's been mutated with any other creature like Sea-Dasher Octopus.
'If you control more than one Essence of the Wild, creatures you control will enter the battlefield as a copy of the one whose copy effect you apply last.'
...and it's in the rules:
616.1. If two or more replacement (…) effects are attempting to modify the way an event affects an object or player, the affected object’s controller (…) chooses one to apply (…)
RULES OF MAGIC :
http://magic.wizards.com/en/game-info/gameplay/rules-and-formats/rules