Rabid is a 1977 horror film directed by David Cronenberg. After a motorcycle wreck a woman undergoes an experimental medical procedure. The results are unexpected. Well, not to us -we're watching a horror movie, after all- but certainly to them.
This film takes place during the Christmas season and has the occasional scene of Christmas-themed shop windows as well as a scene in a department store with kids seeing Santa.
Horror News closes with this: "this movie is still worth a look and is far considerably better than some of it’s era counterparts."