When a smashmouth spread offense is running plays at breakneck speed, motioning blockers all over the field, and utilizing the option, it becomes easy for it to outnumber and outflank the defense, which leads to big plays.
The defense has three recourses: an aggressive quarters coverage that can get nine defenders involved in the run game quickly, an eight-man front with a great tackler at deep safety, or some kind of blitz. This is when the deep bomb comes into play.
Although he caught several crucial passes in Texas' 1969 and 1970 victories that secured consecutive national championships, wide receiver Cotton Speyrer is often an overlooked cog from the first wishbone offense. If you wanted to get your safeties to the line of scrimmage and prevent being out-leveraged by the option, you had to leave someone 1-on-1 with Cotton, and that could mean a quick score for the Longhorns at any point.
The nature of the smashmouth spread can make it fairly easy to spring people deep. Morris will run double moves off fake screens and utilize play-action early and often to see if he can sneak someone downfield for a cheap and easy score.
He also uses vertical concepts like under and four verticals to see if a particular receiver can win a matchup deep, with the QB having a quick checkdown or scramble option available if nothing works out.
As devastating as the option can be, defensive coordinators really start to panic if the offense can run it while simultaneously running a wide receiver deep who cannot be single-teamed. That's the final piece that can make any offense unstoppable.