Activate Shilgengar by sacrificing Crookshank Kobolds.
When Crookshank Kobolds dies, Mortuary and Remembrance trigger.
Resolve the Mortuary trigger, putting Crookshank Kobolds from your graveyard on top of your library.
Resolve the Remembrance trigger, searching your library for Crookshank Kobolds and putting it into your hand.
Resolve the Shilgengar ability.
Cast Crookshank Kobolds by paying 0.
Repeat.
This clever loop turns zero-mana creatures into an endless engine of sacrifice and search. By sacrificing Crookshank Kobolds to Shilgengar, Sire of Famine, you fuel your Blood token production while sending the Kobold to the graveyard to trigger both Mortuary and Remembrance simultaneously. Mortuary places the Kobold right back on top of your library just in time for Remembrance to pluck it straight from your deck and return it to your hand, ready to be recast for free.