Flying (This creature can't be blocked except by creatures with flying or reach.)
Nightmare's power and toughness are each equal to the number of Swamps you control.

: The next 1 damage that would be dealt to this creature this turn is dealt to its owner instead. Only this creatures owner may activate this ability.
When this creature dies, its owner loses half their life, rounded up.

As long as Gaea's Liege isn't attacking, its power and toughness are each equal to the number of Forests you control. As long as Gaea's Liege is attacking, its power and toughness are each equal to the number of Forests defending player controls.
: Target land becomes a Forest until this creature leaves the battlefield.

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than this creature. If you can't, this creature deals 7 damage to you.