The "Big Stig" is one of The Stig's many cousins, and was featured in Series 9, Episode 3. Like many of the cousins, The Big Stig's appearance was brief, but was also a noticeably slow driver.
S9E3 was set in the United States, with the presenters purchasing American cars and driving them across four states whilst on holiday. One of the challenges was for the cars to set a lap time around the Moroso Motorsports Park race track. James and Richard noted that none of them were familiar with this particular track before and it would be difficult, but it turned out they would not be the ones driving. Emerging from a nearby RV with thunderous footsteps, "The Stig's American Cousin" was introduced as the driver, described as "a CIA experiment that went wrong, and that he only eats cheese." Richard nicknamed it The "Big Stig" due to its obese appearance.
The Big Stig then proceeded to set a lap time around the Moroso course of 1 minute 9 seconds for Jeremy's Camaro, 1 minute 14 seconds for James' ponderous Cadillac, and 1 minute 16.9 seconds for Richard's Dodge Ram which struggled on the turns due to poor braking. Jeremy noted the American Stig's "very relaxed driving style" while driving the Cadillac, and Richard blamed the Dodge losing the timed challenge on Big Stig's size. With the lap times set, The Big Stig's work was done.