Raila, Blighted Lightning

Partner
Landfall—Whenever a land enters the battlefield
put a +1/+1 counter on a land that already has a
+1/+1 counter on it. If that land is a swamp, put
X -1/-1 Counters on target permanent where X
is equal to the Land you control that has the
greatest number of +1/+1 counters on it.
{1}{b}{b}{t}: Target player loses X life Where X is
the greatest number of -1/-1 counters among creatures they control.