Phinix, Plague Doctor

Whenever a nontoken creature you control dies, put a virus counter on Phinix, Plague Doctor.
{3}{w}{b}: Deal X damage to target creature and you gain X life, where X is the number of virus counters on Phinix, Plague Doctor.
When Phinix, Plague Doctor has at least 7 virus counters on it, transform Phinix, Plague Doctor.
''They all died of the same disease. It appears to be a virulent fungus...''