Mental nightmare

When the mental nightmare enters the battlefield
it destroys all non-Black planeswalkers and all legendary es creatures. You gain 4 lives for
each card destroyed this way.
{4}{b}{b}{t}: Your zombies or horror creatures gain
the threat ability until the end of the turn.
{c}{c}: No one can play Enchantments or
Spells until it's your main phase again. You lose
2 lives.