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If there's any lesson to be learned from the IKEA monkey, it's that the Internet can make stars out of cute creatures in stores. And this past weekend proved it all over again, when "Alex from Target" took over the hearts and Twitter feeds of teenage girls worldwide:

After this photo inspired countless memes, a rumor circulated that the whole thing was just a marketing stunt—though that theory was quickly debunked, with Target spokespeople stating they were "as surprised as anyone" by Alex's fame. But that didn't keep them, of course, from getting in on the action: Pleased with all the attention, the store tweeted an approving "We heart Alex, too!"

Alex, who is enjoying his new-found fame (and perhaps waiting for his own web game to drop), is hardly the only example of the Internet giving a free gift to brand managers and advertisers.

Here are 6 other brands that went viral.

1. Chevrolet

Last week, a Chevrolet regional zone manager named Rikk Wilde nervously botched a televised speech while presenting World Series MVP Madison Bumgarner with a new Chevy truck. The company took ownership of the resulting viral video by turning Wilde's most embarrassing line — "It combines class-winning and leading, um, you know, technology and stuff" — into a hashtag.

2. Poland Spring

Florida Senator Marco Rubio unintentionally filmed a compelling bottled water ad when he got a dry mouth during the Republican response to the 2013 State of the Union address—and awkwardly grabbed and gulped from a Poland Spring bottle placed off-camera.

3. McDonald's

When Iowa science teacher John Cisna ate nothing but McDonald's food for 3 months (and—crucially—exercised every day), he lost 37 pounds. His experiment, originally designed to teach his students the importance of making smart choices when presented with any menu, led to a supersized Twitter following, book deal, and paid gig speaking to McDonald's franchisee and employee groups. Cisna even kept the experiment going past the 3-month mark:

4. PBS

You might remember when then-presidential candidate Mitt Romney raised hackles during a 2012 debate by saying to debate moderator Jim Lehrer: "I’m going to stop the subsidy to PBS. I’m going to stop other things. I like PBS. I love Big Bird. I actually like you too. But I’m not going to — I’m not going to keep on spending money on things to borrow money from China to pay for it." As a result, at least some public broadcast stations saw a spike in donations, thanks to a "save Big Bird" campaign.

5. Diet Coke and Mentos

A favorite of science teachers and YouTube daredevils alike, this famous viral challenge gives anyone who enjoys harmless explosions an incentive to buy Coke and Mentos. Though the reaction technically doesn't require Diet Coke—just carbonated water—the aspartame in diet soda apparently makes the reaction most powerful.

6. Chipotle

This video, featuring an adorable child professing love for the purveyor of pico de gallo, speaks for itself. So far, more than 2 million people have viewed it.

Now learn more about Alex from Target and check out some examples of videos that brand managers wish you had never seen: