Devil Dog: The Hound of Hell

Devil Dog The Hound of Hell is a 1978 television movie directed by Curtis Harrington. The story centers on a suburban family and the harrowing experiences they endure from a possessed dog they innocently adopt. The film stars Richard Crenna as Mike Barry, the father, Yvette Mimieux as Betty, the mother, and Kim Richards and Ike Eisenmann as Bonnie and Charlie, their children. The latter two starred in Disneys Witch Mountain series.

Realizing the dog is possessed, Mike finally makes a special trip to Ecuador to determine how to destroy the animal. Unfortunately, there is no way to kill it, but if you hold a holy symbol to its eye, you can imprison it in Hell for 1,000 years. He takes it to a showdown at his work plant, but there the dog turns into a demon and begins to wreak havoc. When he is cornered by the monster, he holds the sign he made on his hand right up to the beasts eye. This causes the beast to be engulfed in fire and be imprisoned, getting his familys souls back. The final scene shows the family loading the family car for a vacation, and one of the children mentioning there were several more puppies the vendor was selling, suggesting there are more satanic dogs and that it is not over yet.

Source: Wikipedia