To be a successful college football coach, one must possess an above-average level of intelligence, wit, determination and authority.
The men on this list, in some combination or another, have—or had—the ingredients to make them a force to be reckoned with.
Of course, Bear Bryant gets a shout out for his infamous training camp, but Steve Spurrier and John McKay and their ability to shred with a comment earned a spot as well.
Other guys on this list just earned a spot by sheer virtue of their longevity and dedication to a program.
Whatever the reason, the 25 men on this list earned props as the most intimidating head coaches in history.
Parseghian played halfback in college, a position that was even more physically demanding then than it is today.
He became the head coach of Notre Dame in 1964 and led the Irish to two national titles before departing in 1974.
While not blatantly known for his rough-and-tumble practices, Parseghian gets a spot on this list simply because an opportunity to talk to the man that masterminded Notre Dame's offense during those titles would be a little overwhelming.
Maybe "intimidating" isn't quite the word, but Johnson had to have some sort of charisma and strength to lead the Miami Hurricanes during his time there.
Those were the glory days of the "U" when guys wore fatigues and trash-talked their way to a national title.
Johnson also led the Hurricanes to the 1986 title game, which they lost to Penn State.
Sure, he may not have been the strictest disciplinarian, but he found a way to get it done with a flamboyant group of players.
Hate on him all you want to for his dishonesty and bad decisions at Ohio State, but Tressel had a stellar career, and his intense, serious attitude about football earns him a spot on this list.
When you think about serious coaches, Tressel tops the list.
Tell me that's not a little intimidating for young guys entering the program.
While he won one title with the Buckeyes, he had five titles with the four from 1-AA Youngstown State.
Any man that can eat grass, coach Tyrann Mathieu and win a national title deserves a spot on this list.
His Big Cat Drill is a tough variation of the Oklahoma drill and is one of the toughest drills in sports.
Of course, it's hard to take a man seriously that calls out a recruit that transfers, but either way, he gets some credit on this list.
The Heisman Trophy is named for this man, and if that isn't enough for you, check out his stare.
That's hard enough to melt steel.
Anyway, Heisman was at the helm of Georgia Tech during its infamous 222-0 beating of Cumberland College in 1916.
While the ethics behind such a beating may be questionable, there is no doubt the opposing team—if you could call it that—was probably pretty intimidated.
He also notably said: "Gentlemen, it is better to have died a small boy than to fumble this football."
It's almost a certainty that great coaches such as Amos Alonzo Stagg and Knute Rockne chewed out players that made mistakes.
However, the advent of television and the focus placed on coaches by the networks led to such events as this one with Pelini and quarterback Taylor Martinez.
For my money, that's one pretty intimidating angry face.
Schwartzwalder was the man that recruited Jim Brown.
Point for him.
He also coached Ernie Davis, Larry Csonka and Jim Nance—quite a litany of very good running backs.
On top of that, the man had the strength of character and will to coach and play Davis to the first Heisman Trophy awarded to an African American.
The man deserves more credit than we usually give him.
Dooley coached Herschel Walker.
That's pretty much all you need to know.
Other than that, he amassed 201 wins over his 25-year career, had only one losing season and led his team to a national title.
He was not known for being an intimidating person, but the ability to demonstrate longevity on that scale shows the man had some level of fortitude that seems to be missing in today's coaches.
First, while at SMU, Fry recruited the first African-American player to play in the SWC despite the social outcry over such a move.
Then, later in his career at Iowa, he led the program to three Rose Bowl games, which is one more thanthe total number of bowl games the program had ever reached.
To top it all off, he painted the opponent's locker room at Iowa that legendary pink color. Pretty impressive use of psychology for a football coach, wouldn't you say?
Switzer, with an intense glare such as this, has to be included.
He led the Sooners to three national titles and started off his tenure as head coach with 30 straight wins.
Royal was a bit of an innovator, and that inventive nature led to an incredibly successful career at Texas.
He won Coach of the Year twice, each time from two different organizations, and led the 'Horns to three national titles, 12 SWC titles and 16 bowl games during his time at the helm.
He is credited with inventing the wishbone offense, an innovation that was as ground-breaking for the time as the emergence of the spread has been in the past two decades.
He may not look all that hard from the picture, but Yost certainly had enough impact to leave a mark on college football that has endured for a while.
From the very first season, his teams were incredible, rushing out to an 11-0 record in 1901, and never allowing a point from any opponent.
From 1897-1926, coaching in six different places, Yost incredibly only had one team with a losing record.
Even today, I would hate to look across the field and see this man standing on the opposing sideline.
McKay coached at USC from '60 to '75.
After two losing seasons to start his tenure as head coach, the Trojans had 14 consecutive seasons with a winning record.
During that time, McKay led them to four national titles.
En route, he made a name for himself with his sparkling wit and cutting humor. For instance McKay gave us this gem following a loss: "We didn't tackle well today but we made up for it by not blocking."
Tom Osborne is one of the most legendary icons in college football history.
Walking into a room and meeting this man, while a great honor, would also be extremely intimidating, especially for a fan of the Huskers.
He coached the football team from '73 to '97, leading the Huskers to three national titles and 13 conference titles while never winning fewer than nine games in a season.
He is now the athletic director of the Huskers at the age of 75.
The "The Grand Old Man of the Midway," Stagg coached in some capacity until he was 96 years old.
He spent 40 years at the University of Chicago, where he led the team to two national titles, and had only five losing seasons in 40 years.
He is credited with inventing the end-around, hidden-ball trick, fake punt, quick-kick, man-in-motion, double reverse, huddle, backfield shift, Statue of Liberty play, padded goal posts and numbers on players' backs.
Not even Chip Kelly has that many impressive innovations to his name.
The only coach on this list who is not an FBS head coach, Gagliardi gets the nod for his longevity and incredible success.
In 1949, the first Polaroid camera was sold for $89.95, the average price of a house was $7,450.00 and Bruce Springsteen, Vera Wang and Sigourney Weaver were all born.
That's also the year Gagliardi began to coach.
Four seasons later, he moved to his next coaching position as head man of the St. John's (Minnesota) Johnnies.
Fifty-eight seasons later, he is still going strong and has only suffered two losing seasons over the course of his entire tenure at St. John's.
This guy does not get near enough recognition for his accomplishments.
Bierman coached Minnesota from '32-'41 and again from '45-'50.
During that time, he led Minnesota—yes, Minnesota—to five national titles.
This was a man that left some big tracks behind him.
He punched a player. On the field. In the middle of game play.
The action was despicable and eventually led to his resignation, but there is no questioning the man had some serious intensity—along with the obvious anger issues.
This move led to his firing.
This incident is what he is best known for, but his coaching chops are pretty intimidating, as well.
He led Ohio State to five national titles in his time with the program.
Any coach that earns "Defensive Coach of the Century" honors as Bear Bryant's defensive assistant deserves a spot on this list.
Neyland served as head coach at Tennessee for three separate stints, spanning 21 years and four national titles.
Even more impressive than his football chops is the fact that he served in the Army, eventually as an aide-de-camp for General Douglas MacArthur.
Have you ever seen that Bobby Bowden commercial for Discover?
Here it is.
"I'm not too old to find you, son" is one of the greatest lines in the history of commercials.
He spent the bulk of his great career at Florida State, where he led the Seminoles to two national titles and 12 ACC championships.
Ah, "the Ole Ball Coach."
Spurrier is a little different than the others on this list.
Sure, he has won plenty of games, including the 1996 national title, and he took home the 1966 Heisman Trophy.
For the purposes of this list, however, it's his wits that are intimidating.
Spurrier has been known for some zingers when it comes to quotes, and it might be pretty intimidating for some of us to match wits with someone that quick on the draw.
No, that wasn't even a first down.
And yes, all of Nick Saban's players survived the next practice.
The man can get angry, but it's his penchant for winning that earns him the right to this list.
He has now led the Crimson Tide to two national titles, and also led LSU to the title back in 2003.
On top of all that, Forbes named him the "Most Powerful Coach in Sports."
JoePa is a legend—a once-in-a-lifetime personality that left an indelible mark on the face of college football.
And he was one tough dude.
Check out this list of injuries and tell me that you could have handled them with half of the toughness Paterno did.
For that toughness, both mental and physical, he makes this list.
Rockne, born to Norwegian immigrants who transplanted to Illinois, coached Notre Dame for 13 years and spent another 10 as athletic director.
His all-time winning percentage of .881 is the greatest of all time at that level, and his experience playing the game leads one to believe he was one tough dude.
He led the Irish to three national titles and five undefeated, untied seasons.
You would be hard-pressed to find a coach that inspires more respect to this day.
Sure, we all know about his time as head coach at Alabama and his tremendous success there that included six national titles.
And many have seen the infamous Junction Boys, the story of Bryant's incredibly demanding first camp at Texas A&M.
Both of these—his success and his attitude toward practice—would grant him a place on this list.
However, it's his name that absolutely confirms it.
Former Alabama quarterback Joe Namath put it best: "His nickname was Bear. Now imagine a guy that can carry the nickname Bear."