Hi. First thanks for everything you do to help out the community! i've learned so much since i found your tumblr. I had a blood moon question that came up in a game yesterday. Blood moon is in play and my oppenent has a basic forest and two amulet of vigor. He played vesuva targeting forest and tried to have it come into play tapped. Should vesuva become a forest and should come into play tapped if blood moon is in play? Thank you!
When Blood Moon is on the battlefield, nonbasic lands are mountains from the moment they enter the battlefield. In fact, since they enter the battlefield as mountains, they don’t get any of their own ETB replacement effects or triggers, so they enter untapped with no choices made for them and no counters.
In the scenario you describe, Vesuva enters the battlefield untapped as a mountain and your opponent doesn’t get to choose for it to copy anything.
(This is a rules change that was brought in for Ixalan. Previously, your opponent would be able to choose to have Vesuva enter as a tapped copy of the forest.)