What is the Brimley Cocoon Line?

The Brimley/Cocoon Line is the age in days (18,530) the actor Wilford Brimley was when the movie Cocoon (1985) came out. An actor crosses the Brimley/Cocoon line whenever they get older than 18,530 days.

The movie Cocoon is about a group of elderly people in a Florida retirement home that come across a swimming pool that is being used by aliens to store powerful cocoons. After swimming in the pool, the retirees find themselves younger and they now have regenerative powers.