This gruesome loop turns Shilgengar, Sire of Famine into an engine of endless rebirth by leveraging the clever shapeshifting of Body Double and the lingering resilience of Reveillark. You begin by feeding Body Double—disguised as a copy of Reveillark via its graveyard-targeting replacement effect—to Shilgengar's sacrifice ability, which conveniently generates a Blood token in the process. The moment Body Double leaves the battlefield, its inherited Reveillark trigger fires off, allowing it to crawl straight back out of the graveyard and clone Reveillark all over again. By repeating this cycle, you can endlessly churn through sacrifice triggers and flood the board with infinite Blood tokens, ready to fuel Shilgengar's massive graveyard-returning ultimate whenever you need to overwhelm the table.