Viral videos are a lot of fun — they give us something to watch over and over, share with our friends, and talk about on Facebook. But not every video is as genuine as we first believe; sometimes we find that we've been the victims of elaborate hoaxes.

And even though these aren't as potentially dangerous or damaging as other hoaxes we've seen, it can still be a letdown. Let's take a look at a few that caught a lot of people.

Charge an iPod with an Onion

YouTube videos detailing surprising science-y things can do really well (I especially like Smarter Every Day). But not every home science project that you see on YouTube works. The guys behind HouseholdHacker have posted a number of hoax videos. The most famous of these, posted in 2007, included instructions on how to charge an iPod using Gatorade and an onion.

Why would you want to charge an iPod with an onion? They don't say. To show that it can be done, I suppose.

But there's a problem: it can't. A Gatorade-soaked onion doesn't generate electricity. And even if it did, USB cables need to be plugged into USB ports, not jammed into the sides of vegetables. A lot of people were convinced by this hoax, with the video receiving almost 10,000,000 views.

The MythBusters video debunking the project, however, only has 197,000.

The eHarmony Cat Lady

2011 saw one of the most successful video hoaxes in recent memory, with an eHarmony video bio by "Debbie." Debbie states that she's making her first video for eHarmony, and proceeds to tearfully elucidate just how much she loves cats.

It's a lot.

Turns out that Debbie is actually Phildelphia comedienne Cara Hartmann, who doesn't (as far as we know) have an alarming degree of affection for cats. She does, however, now have a YouTube show called Debbie in LA, which follows Debbie's move to the West Coast after her online dating profile receives 27,000,000 views (in case you're wondering, the video actually has over 29,000,000 views at the moment).

Online dating is hard, and fake videos of cat-obsessed singles don't help the process. But they can be pretty funny.

Petting Zoo Hero

The Internet loves animal videos, especially when they involve more than one kind of animal. It's even better if it involves goats.

This video has all of the elements of a viral sensation. A small pig saves a baby goat from drowning in a pond; what could be more endearing?

The Internet was much less endeared when they found out that the whole thing had been put together by Comedy Central, and some very talented animal trainers, to generate press for a show called "Nathan for You." The video was huge — it was featured on Time, Huffington Post, Yahoo! News, Gawker, ABC News, and many other major outlets. The crew later released a video detailing how they had trained the seemingly life-saving pig:

This hoax actually generated quite a bit of discussion about news outlets' willingness to share videos without doing any fact-checking, and whether or not this is ethical. Kelly McBride, a senior faculty member at Poynter Institute, called it "embarrassing" and "almost a form of malpractice."

Nathan Fielder, of Nathan for You, wasn't phased. He told the New York Times that "[i]f we were trying to pull an elaborate hoax on the news, I think we could have pushed further. But we weren’t. We found it interesting that people were sharing it without us saying anything.”

Golden Eagle Snatches Kid

The heroic pig certainly isn't the only animal that's gone viral. This one is a bit more menacing, though. In the video below, you'll see a golden eagle drop from the sky and attempt to nab a baby—the eagle tries to pick it up and fly away, but drops it shortly after. Considering that golden eagles can have 7-foot wingspans and have been known to kill grey wolves, this isn't quite as far-fetched as it sounds.

Fortunately, this harrowing incident was a fake; the whole thing had been created as a part of a project for a simulation workshop at the National Animation and Design Centre in Montreal. The teacher told Buzzfeed he was trying to come up with new ways to teach the class.

Students were told that if they could get 100,000 views on YouTube, they'd get an A. One of the students discussed their strategy with the Globe and Mail: "We . . . decided to come up with something that involved animals and babies — those seemed to generate the most hits."

He was more right than he knew. The video currently has over 44,000,000 views.

Rayman in Smash Brothers

Nintendo's popular brawler Smash Brothers lets gamers pit popular Nintendo characters against each other in fights —so it was a big surprise when "Rayman Leak Video" hit YouTube, apparently showing that Rayman, a non-Nintendo character, would be included in a DLC pack.

Alas, Rayman fans were let down when they found out that the whole thing was a hoax. The maker of the video posted another video detailing how he created the "leak", and the amount of work that he went through to make a very accurate menu is pretty impressive.

Twerk Fail

Love it or hate it, twerking has had a fascinating effect on pop culture over the past couple years. YouTube is full of home-twerking videos, but none got as many views as one that shows a woman twerking upside down against a door when her roommate enters, knocking her onto a coffee table and setting her on fire.

The utter ridiculousness of the video made some people suspicious, and it was revealed shortly after that the video had been made by Jimmy Kimmel and a stuntwoman, who then made an appearance on his show. (The video below shows Kimmel coming to the rescue with a fire extinguisher after the stuntwoman ignites.)

Lonelygirl15

In 2006, the world was introduced to Bree, a 16-year-old girl who posted quirky YouTube video blogs and interacted with fans via MySpace under her username, lonelygirl15. There wasn't anything particularly special about her videos; she just talked about her life, and seemed sweet.

In 2008, it was revealed that "Bree" was, in fact, a 19-year-old actress named Jessica Lee Rose, and that the video blogs were in fact episodes of a fictional show. Many people had suspicions about the videos, citing minor inconsistencies, and it became clear quickly that things were not normal in Bree's world. Her parents disappeared, there were hints of cult involvement, and things got progressively more weird.

The show, LG15, has continued with a number of spinoffs detailing the exploits of the Order, an evil organization searching for "trait positive" girls — and now includes vlogs from a number of characters.

Facebook Friends Sleeve

Facebook tattoos aren't super common, but they've definitely been done before. YouTuber susyj87 brought it to a new level with an entire sleeve made up of the profile pictures of her Facebook friends.

Of course, this one was debunked fairly quickly, as the owner of the tattoo stop stated that it was a temporary tattoo that would only last a few days. The video was organized by Pretty Social, a company that says people "are proud of [their] (large) social network online, that we carry with us every day through various media. Pretty Social also provides this in an offline format."

Just to be clear: Pretty Social is not a social-media tattoo parlor.

Sochi Fail Wolf

The popularity of the #SochiFail hashtag brought a lot of pranksters out of the woodwork, with some hilarious — and some not-so-hilarious — results. This video, by US luger Kate Hansen, features a wolf walking through the athletes' dorm. It was just another example of how things were going wrong in Russia.

Or was it? While this does actually show a wolf walking through the hall, it wasn't a wild Russian one: it was a trained American wolf named Rugby. This was another video hoax by Jimmy Kimmel (Hansen was in on it),  showed on news stations around the country. Sochi security even got involved.

Don't Trust Your Eyes

It's long been an adage that you shouldn't believe everything you read, especially on the Internet. The same applies to online videos, and to Instagram. Next time you see a video that seems too spectacular to be true, stop and think about it for a moment. It probably is!

Were you caught by any of these hoaxes? Have others been more convincing? What are your favorites? Share your thoughts below!