Rot Hulk by paying ({5} magic symbol) ({B} magic symbol) ({B} magic symbol) .
Rot Hulk enters the battlefield, triggering its ability.
Holding priority, activate
Carrion Feeder by sacrificing
Rot Hulk, putting a +1/+1 counter on
Carrion Feeder.
Resolve
Rot Hulk's trigger, returning
Phyrexian Delver and
Gray Merchant of Asphodel from your graveyard to the battlefield.
Gray Merchant of Asphodel and
Phyrexian Delver enter the battlefield, triggering their abilities.
Holding priority, activate
Carrion Feeder by sacrificing
Gray Merchant of Asphodel and
Phyrexian Delver, putting two +1/+1 counters on
Carrion Feeder.
Resolve the
Gray Merchant of Asphodel trigger, causing each opponent to lose life equal to your devotion to black, and causing you to gain life equal to the life lost this way.
Resolve the
Phyrexian Delver trigger, returning
Rot Hulk from your graveyard to the battlefield and causing yourself to lose 7 life.