Activate Ashnod's Altar by sacrificing Magus of the Coffers, adding ({C} magic symbol) ({C} magic symbol) .
Activate Magus of the Coffers' unearth ability by paying ({2} magic symbol) ({B} magic symbol) , returning it from your graveyard to the battlefield, giving it haste and exiling it at end of turn or when it leaves the battlefield.
Activate Magus of the Coffers by paying ({2} magic symbol) and tapping it, adding at least six ({B} magic symbol) .
Activate Ashnod's Altar by sacrificing Magus of the Coffers, adding ({C} magic symbol) ({C} magic symbol) .
Both Magus of the Coffers's undying ability and Void Maw attempt to exile Magus of the Coffers when it would be put into your graveyard.
Choose to apply the Void Maw replacement effect, exiling Magus of the Coffers.
Activate Void Maw by putting Magus of the Coffers from exile into your graveyard, giving Void Maw +2/+2 until end of turn.