Multiple Mirror Effects in Movies

Conan The Destroyer (1984)

Spoiler Alert !

Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
 
screenshot screenshot screenshot
screenshot screenshot screenshot

Conan breaks into a wizard's island castle to rescue a kidnapped princess. He walks into a large room with walls covered in curtains. When the curtains are raised we see that the walls are made of mirrors. Several figures in orange robes walk out of the walls then they merge into a large monster that fights Conan. Conan's sword can't injure the monster until he accidentally smashes the monster's reflection in one of the mirrors. Conan then starts smashing all of the mirrors until the monster falls to the floor dead.
Scene starts at about 39 minutes.

Watch the scene on YouTube