A baby is found buried alive in shallow ground and appears to have birth defects resulting from generations of inbreeding, leading Mulder and Scully to a reclusive family who have a history of inbred children.
Wonderful! Wonderful! (Single Version) — Johnny Mathis
The Peacock's take off in their car at night and go murder the sheriff; returns at the end with Mrs Peacock in the car's trunk telling Edmund they'll repopulate