Coca-Cola (KO) is shooting down the idea that it might buy Monster Beverage (MSNT), sending shares of the energy-drink maker down after a wild trading day.

Coke sent out a pretty definitive denial late Monday. "At this time, we are not in discussions to acquire the Monster Beverage Corporation," the company said in a statement. "We continue to review the best ways to maximize the value of our relationship."

That statement effectively erased all the gains Monster shares made Monday after The Wall Street Journal reported that Coke was in talks to buy Monster. Our partner Benzinga reported the same thing last week.

Monster opened Monday at $65.54 and soared as high as $83.96 -- a 28% gain -- on huge trading volume. The share gain was so intense that trading was halted twice Monday for about five minutes each, Forbes reports.

Coca-Cola shares lost less than 1% Monday to close at $76.32.

So how did this rumor take off? That's unclear. But some people made and lost a bunch of money on Monster Monday.

The following video has some details on why people thought Coke would be interested in buying Monster.