Movie In-Jokes: Hellboy

One of the fun games when watching movies is to spot references, secret messages and gags that filmmakers, film crews and actors can slip into movies to pay tribute to films they love, have a bit of fun with their previous work, or give the cinematic equivalent of a shout-out. Here's a spotter's guide to these inside jokes.

This in-joke comes from the imaginative cinematic universe of Guillermo del Toro and suggests that the Bureau for Paranormal Research and Defense from Hellboy has been busier than we thought.