Restless Fortress
Land
This land enters tapped.
: Add 
or 
.
: This land becomes a 1/4 white and black Nightmare creature until end of turn. It's still a land.
Whenever this land attacks, defending player loses 2 life and you gain 2 life.
Legality
standardLEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL