When Kitchen Finks dies, its persist ability triggers, returning Kitchen Finks from your graveyard to the battlefield with a -1/-1 counter on it.
When Kitchen Finks enters the battlefield, it triggers, causing you to gain 3 life.
Cleric Class triggers, putting a +1/+1 counter on Kitchen Finks.
Resolve the Shilgengar ability.
Repeat.
This resilient loop turns the humble Kitchen Finks into an endless sacrifice engine under the watchful eye of Shilgengar, Sire of Famine, who eagerly turns each demise into a steady stream of Blood tokens. The secret to sustaining this cycle indefinitely lies in Cleric Class: its static lifegain buff and level two counter-placement neutralize the persist -1/-1 counter by immediately placing a +1/+1 counter on the Finks upon its return. Because +1/-1 counters mutually annihilate each other as a state-based action, the Finks is effectively cleansed and ready to be sacrificed to Shilgengar all over again.