Rory: They said 'hello' to me the other day.
Lorelai: Really!? Like a normal hello, not like a "Heeere's Johnny!" kind of hello?
Rory: Normal. Friendly. No axe.
Lorelai: Wow, you're the new Heather!
"Here's Johnny" was the introductory phrase for many years for Johnny Carson on the Tonight Show. It was co-opted by Jack Nicholson for the 1980 Stanley Kubrick production of Stephen King's The Shining. In the movie, Nicholson's character, Jack (John) Torrance, has gone insane with cabin fever while "housesitting" as a caretaker at a large northern resort hotel. His wife has locked herself and their son in one of the rooms, and Nicholson breaks a hole in the door with an axe. Staring through the face-sized hole in the door, and with one of his patented leers, he announces, "Heeere's Johnny!" in a classic scene.
Heathers is a classic 1989 dark comedy about coming of age, teen angst, and conformity, with a pair of excellent performances from then-new stars Winona Ryder and Christian Slater. The plot centers about a clique at a high school, all of whom are named "Heather", and which Winona gets involved with. However, also she meets up with "J.D.", a problem child who leads her on a dark path of murder and mayhem,. Slater portrays J.D with a style clearly inspired by Jack Nicolson.