During the years that Berger was at McLaren (1990–1992), he became most famous for his humorous side. Popular accounts tell of many ingenious practical jokes thought up by the Austrian to break through his serious, focused and unyielding teammate – Ayrton Senna. Senna, accepted the challenge, and quickly submitted, and was both were spurred on by team manager Ron Dennis the practical joking escalated.

Accounts tell of an incident at Monza where in a joint helicopter ride Senna had been showing off his new tailor made briefcase. Having been made of carbon fibre composite, Senna argued that it should be virtually indestructible. Berger, without much hesitation and much to Senna’s disbelief, opened the door of the helicopter and threw the briefcase out, to test the hypothesis.

“It fell somewhere near the course but we found it again,” Berger recalled with a cheeky grin.

Australia, 1990, several days before the race. After dinner, we started to throw people in the swimming pool, all dressed. As I was good at defending myself, I escaped from the bath, but many people got wet. Senna ran away to avoid us from getting him, however, later, I went to his room and he awkwardly threw a glass of water at me. For a Tyrolean, that was nothing, but it did mean that the game was now on. With a hose, we improvised an extension to the fire extinguisher and we put it under his room door at three in the morning. We invited some people to watch and when we pushed the lever, Senna flew out of the window like a rocket. It looked like a bomb had exploded inside the room. The confusion woke many people up, who started to scream at Senna for making so much noise. He was terribly embarrassed. (From the book “Na Reta de Chegada”, author Gerhard Berger, Editora Globo, page 76).

On another occasion, in an Australian hotel room Berger filled Senna’s bed with animals. Senna understandably infuriated, confronted Berger by saying;

“I’ve spent the last hour catching 12 frogs in my room,” to which Berger replied, “Did you find the snake?”

“Actually they weren’t frogs, they were bigger, more like toads. In Australia they have this kind of stuff. I thought he liked animals but clearly not,” Berger explained. It was an incident that prompted retaliation by Senna, who then proceeded to put a strong smelling French cheese in the air conditioning unit of Berger’s room.

On another occasion, Senna and Brazilian compatriot Maurício Gugelmin decided to fill Berger’s shoes with shaving foam on a fast train ride to a dinner in Japan. Having been forced to attend the dinner wearing a tuxedo with running shoes, Berger vowed for retribution. It was at the Japanese Grand Prix a few days later that Gugelmin (driving for Leyton-House) was approached by Joseph Leberer, the McLaren team nutritionist, offering fresh orange juice. Ever vigilant, Maurício declined the suspicious offer. He would later expand:

“One hour before the race starts he crushed four sleeping pills into that juice and sent it to me. I would pass out at the start of the race in which the world title would be decided. The cars roaring by at the track and I snoring in the cabin, can you imagine it?”

Best known is probably an incident in which Berger replaced Senna’s passport photo with what Ron Dennis described as “an equivalent-sized piece of male genitalia”. Senna’s fame meant he rarely had his passport checked, but on a later trip to Argentina Berger’s prank resulted in officials holding the Brazilian for 24 hours. As a response to this gag, Senna superglued all of Berger’s credit cards together.

Another incident occurred years later at Ferrari, when Berger and fellow F1 driver Jean Alesi were taking a ride with team director Jean Todt’s new special made Lancia roadcar at the very first testing day of the 1995 Formula One season. Arriving at the test track, Jean Alesi lost control of the car after Berger unexpectedly pulled the handbrake. Having flipped the car, skidded upside down to a halt in front of the entrance and Alesi having been sent to Hospital, Berger admitted to Todt who wanted to know what happened to his car that they had put “slight curb marks on the roof”.

source: Wikipedia