Nightmist Lurker

Skulk
Whenever Nightmist Lurker loses life, target player loses X life and you gain X life, where X is the difference between Nightmist Lurker's maximum toughness and its current toughness.
Some will say that it's just a restless spirit, some will also say that it's the guardian of that forest itself. Nobody really knows what it really is even it resembles like a stag.