It's Wall Street's version of Halloween. Later this month, companies will don their frilliest disguises, knock on doors, and open their bags wide to let investors catch a peek at how their September quarters panned out. Earnings season can be a pretty exciting time, with hundreds of companies lining up to report on any given day.

It can be a pretty hectic time too. Investors nibble away at their nails as Mr. Market opens the door. The moment of truth beckons, and there's really only one question worth asking as the porch light flickers: Trick or treat?

Unfortunately, we've already got a few tricks on the way. Some companies have already alerted shareholders that they will be coming up short in their upcoming quarterly check-ups. Some of them have reasonable excuses. Others are just reaching in the justification process. Let's take a look at a few companies that are already making plans to disappoint investors later this month, eggs in one hand, toilet paper roll in the other.

Wendy's (NYSE:WEN): Hot and juicy? Let's go with cold and dry. The world's third-largest burger chain claimed that rising beef prices and Hurricanes Katrina and Rita squeezed operating profits at both ends. The hurricanes are likely to be a popular blame-game topic as many chains had to close stores for days -- if not weeks -- in the affected areas. However, it's not as if Ohio-based Wendy's has an unusual concentration of units along the Gulf coast. That's why it will be important to see how its burger rivals stack up later this month. If food costs stung Wendy's, they are likely to ding its competitors. If not, feel free to call Wendy's out with your best impression of the "Where's the beef?" lady.

Wright Medical (NASDAQ:WMGI): Two wrongs may not make a right, but one Wright can certainly make a wrong. The orthopedic-parts specialist booted its original third-quarter forecast when it announced that profits would be coming in between $0.10 and $0.11 a share. Its original target had investors banking on profitability of $0.16 to $0.18 per stub. The maker of replacement hips, knees, and orthobiologics faulted weakness in its biologics business as the cause for its quarterly malaise.

La-Z-Boy (NYSE:LZB): Proving that fundamentals can recline too, Income Investor newsletter recommendation La-Z-Boy also missed its mark. The furniture giant had a unique spin on the hurricane excuse. It claimed that the storms disrupted its chemical suppliers, limiting its ability to produce polyurethane foam. That's a critical component of the company's core recliner and sofa products. Disruptions in the supply chain are a legitimate beef, though they should also serve as a wake-up call for La-Z-Boy to ensure that its core supplies don't have a geographical concentration in the future.

Lexmark (NYSE:LXK): Running low on its black ink cartridge, Lexmark also failed to impress equity aficionados. The printing specialist revealed that third-quarter sales would come in 4% to 5% below last year's level. When it steps up to the podium come October 25, earnings will clock in between $0.40 to $0.50 a share. If that doesn't sound too bad, consider that back in July, Lexmark figured that its third-quarter net income would be more than twice that amount. The company faced soft demand for its flagship laser and inkjet supplies despite aggressive pricing measures. That's definitely not a good sign. If cheaper prices won't move your wares, it's time to change your brand of deodorant. Thankfully, Lexmark is a cash-rich company serving a cash-flow-rich niche. The company should bounce back eventually, but it won't be doing so this year. The company made it a point to shoot down analyst targets for the December period as well.

Knight Ridder (NYSE:KRI): What's black and white and red all over? The newspaper industry! At least that's the way it seemed last week when paper publishers like Knight Ridder were announcing either September-quarter shortfalls or another wave of layoffs. Knight Ridder's southeastern exposure clearly opened it up for a hurricane-related excuse, but the industrywide problems run deeper than that. Many publishers took to faulting Detroit as "employee pricing" promotions by American auto manufacturers dried up the need for local dealers to buy automotive ads. But that's not the real problem. Online advertising continues to grow at a rapid clip, and it is coming at the expense of traditional sponsorship channels like television and newspaper. The excuses are gone, but chances are pretty good that the weakness will continue in the near term.

Silver linings for golden opportunists
The laundry list of profit-warning reports shouldn't trouble you. Sure, they're plentiful. Go alphabetical and it will take you a long time to get past the very first letter as companies like aluminum giantAlcoa (NYSE:AA) and ADC Telecommunications (NASDAQ:ADCT) have also let the investing public know that they blew it this time.

However, the fact that there have been so many warnings -- and so few upward revisions -- isn't as big a deal as you may think. Companies are quick to report bad news for fear of litigious shareholders. When they have good news to tell, they usually don't mind keeping it under wraps and springing it on delighted investors later. That's because no one ever sued a company for being too good.

So don't be afraid when the doorbell rings later this month. Earnings season is usually a festive time. Just be careful of what candy you give to that corporate kid decked out in the grim reaper outfit.

Longtime Fool contributor Rick Munarriz dreads the early reports almost as much as the Friday night press releases. He does not own shares in any of the companies mentioned in this story. The Fool has a disclosure policy. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.