He rants, he gesticulates, he curses, he swears. Sometimes, his face becomes contorted with sheer exasperation and he appears as if he will either pass out or explode.
Of the 32 coaches at the World Cup, none seem to live the tensions of the touchline with such intensity as Brazil's Luiz Felipe Scolari, known to most of his compatriots simply as Felipao (Big Phil).
A charming, likeable man off the field, Scolari -- who has rescued Brazil from the doldrums and turned them into World Cup favourites -- is transformed as soon as the referee's whistle starts a game.
His theatricals are a show in themselves, so much so that Brazilian television stations often keep a camera focused on him for the entire game.
Yet the sanitised surroundings of the World Cup, combined with the responsibility of leading his country, appear to have taken the wilder edge off Big Phil.
Back in his native Brazil, Scolari earned a reputation as a master of gamesmanship and for pushing the rules to their limits.
When he was a club coach at Palmeiras, he was once accused of ordering the club's ball boys to throw spare balls onto the field. The idea was to disrupt the opposition's attacks as they pressed for an equaliser late in the match.
Scolari was also a specialist in standing on the touchline and bullying referees and linesman, who are subject to political pressures behind the scenes in Brazil and are more easily intimidated than when the entire world is watching.
On one of the occasions that Scolari was sent off for his behaviour, millions of television viewers witnessed him inviting the referee to settle matters in the car park afterwards: "I'll wait for you outside, mate," he yelled as the touchline cameras homed in.
Reporters were also fair game, and at least two complained that they have been punched by him in separate incidents.
Brutally honest, Scolari publicly berated his players for not committing enough fouls and said his fellow coaches all did the same. "The truth is that I'm stupid because I tell the truth while the others lie," he said.
Scolari has already been sent off since becoming coach of Brazil.
During a Copa America match against Paraguay, Scolari celebrated a Brazilian goal by making an offensive gesture at the referee and was ordered from the bench.
But in typical Scolari style, he wriggled out of having to watch the game from the stands. Instead, he hid on the stairs that lead down to the dressing rooms with only the top of his head above the surface and scuttled inside like a giant crab every time officials looked in his direction.
Since then, he has mellowed so much that one reporter asked him what had happened to the old Scolari.
"Do you want me to pull some faces," he replied, before insisting he was still the same.
"When I pick a player for Brazil, I expect him to show the same qualities which prompted me to select him in the first place. And the same goes for me, I will continue to use the qualities which earned me the chance to coach Brazil."
It is not just Scolari's behaviour that has been transformed.
As a club coach, Scolari had a reputation for turning workmanlike teams into title-winners through dedication, hard work and tactical obedience.
He led Gremio to victory in the Libertadores Cup -- South America's equivalent of Europe's Champions League -- in 1995 and won the same trophy with Palmeiras four years later. He is seen as a specialist in the art of winning knockout matches.
Having taken over Brazil with the team at a low ebb one year ago, his first move was to do the same as he had at his clubs. It worked and, under Scolari, Brazil avoided the catastrophe of not qualifying for the World Cup.
When he picked his squad for the finals, Scolari said he wanted his team to be a family -- from which veteran striker Romario, who has a reputation for being a disruptive influence, was left out.
He is also protective of his 'family'. He may give his players hell from the touchline but when the media criticises them, he defends them to the hilt.
Scolari, however, has done something at the World Cup that he has never tried before in his career -- gambled on the individual talents of his players.
His Brazil team look excellent going forward and shaky at the back.
But rather than a change in philosophy, Scolari is simply proving once again that he is a pragmatist who will use whatever method he considers most suitable to win a tournament -- be it good, bad or ugly.
The man who has always built his team on the pillars of marking, strong defending and teamwork this week talked of improvisation and the talent of his players as the key to winning Friday's quarter-final showdown with England.
"I would never inhibit the creativity of a player," he said. "Maybe a piece of improvisation could be decisive on Friday."
"Our forwards have a lot of qualities and they can all play in various part of the pitch, they can change positions and this helps the coach a lot," he added.