"Well that ruined everything". Yep, announcers said it well. With just 10 laps to go in the 2019 Daytona 500 Paul Menard makes a mistake by riding up too close and just barely clipping Matt DiBenedetto on the far right side of the car, and then Matt and Paul's cars turn sideways and take out a grand total of 19 other cars behind them in a massive pile up that certainly qualifies as being called the 'Big One' wreck.
Sparks fly all over the track and smoke completely fills the area, really leaving no choice for any of the drivers in that bunch just behind the lead driver to steer clear of the wreckage. Caused tons of damage and essentially half the field was knocked out of contention from that move alone.