Insatiable Hemophage
Creature — Nightmare
Mutate 
(If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Deathtouch
Whenever this creature mutates, each opponent loses X life and you gain X life, where X is the number of times this creature has mutated.
Steve Ellis
Magic Online Promos (PRM)
• #81007Rulings
In a Two-Headed Giant game, Insatiable Hemophage’s last ability causes the opposing team to lose life equal to twice the value of X and you to gain X life.
(wotc • 2020-04-17)
Rulings
In a Two-Headed Giant game, Insatiable Hemophage’s last ability causes the opposing team to lose life equal to twice the value of X and you to gain X life.
(wotc • 2020-04-17)