Old horror movie from 80s or 90s. I was a kid so remember just a couple of images. There were 2 grannies (two? or just one?) they arranged a party. They were presented a small box, evil smoke went out of it and turned grannies into demons (zombies). During the celebration there nails grew to long claws. Eventually they began to kill everybody (pretty obvious). I remember another scene: they catch a guy who was religious, they gave him a gun and said something like: you have to options: to be tormented by us or to commit a suicide and you will end up in hell. And the gut killed himself.
Sorry for so fragmentary description. Thank you for any help.