"Only if it turns out that reality is actually nothing more than a holographic illusion created by the interplay of subatomic particles on a vast two-dimensional membrane."
This article covers a subject that has been deemed non-canon by either the author or the Back to the Future licensees, and thus should not be taken as a part of the "real" Back to the Future universe.
Marty McFly tries out Mr. Sneeze
Mr. Sneeze was an invention by Doc Brown. It is a wearable tissue dispenser that is meant to be worn on the head.