A Florida McDonald's cashier was shocked after 250 people paid for the food of the person behind them in her drive-thru line.

Marisabel Figueroa said the heart-warming chain reaction happened after Lakeland customer Torie Keene asked for her to pay for the food of the people behind her and wish them a "Merry Christmas."

Those customers asked to pay for the food of the people behind them — and soon hundreds of people followed suit.

"It kept going and going," Figueroa told ABC News. "After the 15th car I started tally marking the number of people that were participating on a piece of paper."

The chain reaction lasted nearly the duration of Figeuroa's six-hour shift.

"I just kept giving everyone the same message, and they were all so stunned and so happy," she told ABC News. "One lady even paid for the meals of the next three cars behind her."