At the beginning of each end step, if a creature died this turn, create a Food token. (It's an artifact with ", , Sacrifice this token: You gain 3 life.")
Old Flitterfang turns every creature death into Food, fueling a mono-black aristocrats/sacrifice engine that grinds value while building toward lethal damage or drain. You sacrifice cheap creatures and the Food it makes to trigger death payoffs, then pump Flitterfang to swing in the air or close with mass drain. The deck snowballs in long games as Food piles up and your sacrifice loops generate inevitability.
Generates incremental value every turn just by creatures dying anywhere on the board
Mono-black gives access to elite tutors, recursion, and removal
Food synergizes with lifegain and artifact payoffs for engine flexibility
Built-in evasive threat that can grow into a real clock
Flitterfang's own pump ability is mana-hungry and not a fast win on its own
Single-color means no access to blue counters or red/green ramp diversity
Relies on a steady stream of dying creatures—gets choked by graveyard hate
Vulnerable to creature removal stalling the death triggers