Hey guys, it’s hump day! Each Wednesday, two important changes occur: workers everywhere can officially start thinking about the end of the week, and Geico sees a spike in shares for one of its most popular ads.

Most consumers have by now seen the ad in question, which claims that people who switch to Geico insurance are “happier than a camel on Wednesday.” It is a funny spot because it features a camel talking in a silly voice, and at first glance it doesn’t seem as if there’s much more to it than that.

On the contrary, the hump day ad is actually taking advantage of a rare but effective method for encouraging shares. It has scored more than 6.2 million YouTube views and has been shared 1.78 million times across social media platforms, but the most interesting tidbit concerns the timing of those shares. According to Unruly‘s recent Q2 report, two thirds of the ad’s shares have come on Wednesday. A graph reveals dramatic spikes coinciding with hump day:

Who knew friends and coworkers looking for a way to be both funny and relevant in the middle of the week could have such a dramatic effect on share patterns? This sort of phenomenon has been seen in the past, but only rarely. We’ve only heard about two other videos with similar spikes. Pop quiz: Can you name them?

One of them is easy. It’s Rebecca Black’s Friday. The other one is a little trickier: Budweiser’s 9/11 tribute ad from the 2002 Super Bowl, which receives a spike in shares on the anniversary of September 11th.

The unique share pattern is more than just an interesting anecdote. The hump day ad has been far and away the most viral entry in Geico’s ‘Happier Than‘ series, and it will surely receive more Wednesday shares for a few more weeks. Clearly, the key to hitting the big time is mentioning a day of the week. Advertisers should start spinning their gears to figure out a way to work a bad case of the Mondays into an upcoming campaign.