Shilgengar, Sire of Famine + Builder's Talent

Steps

1. Activate Shilgengar's first ability by sacrificing the persist creature.
2. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Shilgengar ability, creating a Blood token.
4. When the Blood token enters the battlefield, Builder's Talent's second ability triggers, putting a +1/+1 counter on the persist creature.
5. Repeat.