That’s what happens when advertisers must spend an average of $5 million merely to secure a 30-second commercial slot. And, it’s true that any one of the many companies shelling out big bucks to advertise during Super Bowl LI could come away with an ad that keeps viewers buzzing long after the game airs on Feb. 5. But advertisers seeking brand visibility and goodwill on the nation’s largest stage are also risking major disappointment if their very expensive ad falls flat with viewers amid the sea of big-budget commercials.

Hoping to get the most bang for their Super Bowl buck, companies are increasingly spending additional money on all-out marketing blitzes that are meant to hype their ads in the weeks leading up to the big game. (Look here for Fortune‘s running list of Super Bowl ads that have premiered online already.) In fact, one marketing executive told The New York Times that it’s common for advertisers to spend an additional 25% or more of the cost of their commercial slot just on promoting the ad in the lead-up to the Super Bowl.

One of the ad campaigns that’s already getting quite a bit of buzz is one from Snickers, with the candy bar brand bringing on Star Wars actor Adam Driver for what it promises will be the first-ever commercial to air live during the Super Bowl. The Mars-owned brand even released a handful of teaser ads, including supposed casting call videos featuring a horse, and Snickers said it will air a 36-hour livestream from the commercial set leading up to the big game.

According to the Times, Mary Scott, a president at global marketing agency United Entertainment Group, advises her clients to spend at least 25% of the cost of their commercial slot on marketing the ad itself. As we’ve seen in the weeks leading up to the Super Bowl, those marketing efforts can include extensive social media campaigns, rollouts of short teaser versions of the big game commercials, and events to announce new marketing campaigns. Google’s YouTube also encourages users to vote for their favorite Super Bowl ads (many of which are available before the game) each year with its YouTube AdBlitz.

Advertisers must also contend with the potentially high production costs of putting together a commercial that may be only a minute long, or less, but which often needs a big budget if it’s going to stand out. The average production cost for a Super Bowl ad in recent years was reportedly north of $1 million, as many glitzy ads employ major creative agencies and advertising houses, while some even enlist big-name Hollywood directors and actors. For example, the Academy Award-winning Coen brothers directed a 60-second ad for Mercedes-Benz that stars iconic Easy Rider actor Peter Fonda for this year’s Super Bowl.

This year’s ad blitz will come during an uncharacteristic 8% ratings drop for NFL games during this season. It’s possible that combination of slumping ratings and the exorbitant cost of just 30 seconds of air time during the Super Bowl could cause some advertisers to think twice about opening their wallets for the Super Bowl.

The Super Bowl is typically the most-watched television event of the year in the U.S. Last year, it drew nearly 112 million viewers, just shy of the record 115 million people who watched the game in 2015. That’s a huge platform for advertisers to pitch beer, luxury cars, and many more shiny products.