This ingenious loop starts by feeding Scuzzback Marauders to Shilgengar, Sire of Famine's sacrifice ability to manufacture Blood tokens. The moment Scuzzback Marauders hits the graveyard, its persist mechanic triggers its return to the battlefield with a -1/-1 counter, which instantly invites Stalwart Successor to step in with its static-triggered ability; because putting that -1/+1 counter on the Marauders counters out the -1/-1 counter, the creature is left clean and ready to be sacrificed all over again. By cycling the Marauders through this graveyard-and-return dance fueled by Stalwart Successor's counter neutralization, you can generate an endless harvest of Blood tokens and continuous death triggers.