There are movies with heads exploding and then there's David Cronenberg's "Scanners." The 1980 sci-fi film is still one of the director's finest hours, and one of the best the genre has ever seen. But most of all, while some movies from the era haven't aged very well, "Scanners" has one sequence that is still jaw dropping to this today.

Yep, we're talking about the the moment when Louis Del Grande's head gets magnificently blown up. But as you might expect, it wasn't an easy effect to pull off believably. And in this brief featurette, courtesy of The Criterion Collection who released the film on DVD and Blu-ray last week, Cronenberg and members of the VFX team share how they finally got the shot. And the story is pretty terrific, and we're not going to spoil it here to except to say that sometimes necessity is the mother of invention. Watch below.