Strix parasitario

Parasitic Strix

Flying
When this creature enters, if you control a black permanent, target player loses 2 life and you gain 2 life.

After finding no sustenance on the edges of Grixis, it turned to the skies of Bant.

Double Masters

Flying
When Parasitic Strix enters the battlefield, if you control a black permanent, target player loses 2 life and you gain 2 life.

Salvat 2011

Conflux

Flying
When Parasitic Strix comes into play, if you control a black permanent, target player loses 2 life and you gain 2 life.

If you don't control a black permanent immediately after Parasitic Strix enters the battlefield, its ability doesn't trigger. If you don't control one as the ability resolves, no player loses or gains life. It doesn't have to be the same black permanent both times, however.

Parasitic Strix's ability triggers only once, no matter how many black permanents you control beyond the first.