Deadly Blessing (1981)

Ernest Borgnine is a scary bearded Hittite with crazy eyes who don't cotton to no city folk marrying his kin and laying claim to his sect's land.  When his son Jim, who returned to a farm in the community after graduating college, is killed, the family land is left to his big-city-girl wife Martha. Oh that just won't do.

A couple of Martha's girl friends decide to stay at the farm to help her through her time of grief.  They are all witness to the sect's harassment, and quest to get the family land back. Yikes!

The Sheriff tells her she should leave, but she won't be scared off her land.  She may want to rethink that since now the little band of religious zealots are planning retribution against the hideous Incubus, and according to them, she's the Incubus.

The movie is more like Children of the Corn than what is portrayed on the cover.