Looks like somebody's been slipping some of HansenNatural's (NASDAQ:HANS) Monster energy drink to investors. This stock has been on an absolute tear for the past two years -- increasing almost 17-fold by my rough estimation.

And why not? Growth at this beverage marketer-distributor has been superb as its Monster energy drink continues to gain share in this torrid market category. In the second quarter, net sales climbed by about 85%, and both operating income and net income roughly tripled.

As veteran Fools might have suspected by this point, this stock is now firmly in the hands of the go-go growth crowd. The average daily trading volume for this puppy is more than half a million shares, but the public float is only about 6 million. Do the math and you see that the entire free-floating equity base of this stock turns over roughly once every 11 days. By way of comparison, it takes about 500 days for Coca-Cola (NYSE:KO) to turn over its float and more than 600 days for Pepsico (NYSE:PEP) to do the same.

Setting aside the insanity of the trading, what about the underlying business here? It's actually pretty interesting, I'm happy to say. Hansen outsources its production and packaging, and, as a result, the margins and internal rates of return look very strong. What's more, insiders own a big chunk of the shares, but not so much as to run completely roughshod over other shareholders.

While the company has long run a nice little natural soda, tea, and juice business, energy drinks have supplied the jolt to financial performance. Simply put, the energy drink market is on fire in the U.S. right now, with sales of about $1.6 billion last year and growth of more than 50%. Privately owned Red Bull is the granddaddy of the space (and has about 60% share), but offerings such as Pepsi's SoBe and Rockstar (distributed by Coke) are growing.

Now, I know what some of you are thinking: "This is just a fad." Yeah, it probably is. Most fads fail and fade away (Atkins, anyone?), but a few of them become trends, and a few of those trends become habits. Remember, cola-flavored soda, automobiles, and television were all thought of as fads at one point, too.

It's tough and tricky to compare consumer preferences around the globe, but energy drinks have long been popular in Japan. And if U.S. penetration gets anywhere close to that seen in Japan, there's plenty of growth potential ahead.

Quite frankly, there's no way I'd touch this stock today even though valuation doesn't seem ridiculous. With such frenetic trading activity, it is not hard to imagine a little hiccup hitting the stock. Many of these energy drinks are loaded with stimulants. What happens if some lunkhead guzzles a dozen of them before a football game and develops a temporary heart arrhythmia? Even if it's not a Hansen product, it's going to scare the fast-money investors out of the stock and make for an ugly day or two.

One way or another, though, this will be a fun stock to watch. I'd like to see a little bit better disclosure in the financial release (like a balance sheet and cash flow statement), and I wish members of management would slow down its machine-gun-style delivery on the call (maybe they drink a bit of the product beforehand?). All that aside, it will be interesting to see whether the promise of energy drinks like Monster live up to the frenzy in the market.

More high-energy Foolish takes:

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).