The Brides of Christ is a group of nuns that appeared in "When You Wish Upon a Weinstein". Their headquarters have a machine that can detect whether a Christian is experiencing the ways of another religion, or of a more extreme sense, converting.
In the episode, Peter Griffin, a Catholic schoolboy growing up, is unsure whether he is allowed to put on a yamikah at the synagogue which Max Weinstein is a member of and at which he invites them to attend services. Once he does, he shows up on the organization's monitor, so they grab their rulers and pursue him for the rest of the episode, even all the way to Las Vegas when he wants his son Chris to become smarter by becoming Jewish and Bar Mitzvah'd. However the bus that he, Chris, and wife Lois take on the way back home is the main bus used by the Brides of Christ. When the Brides realize that he's on the bus, they surround him and his family and begin attacking them.