FORTUNE — There’s something about mascots and frivolity that make market observers vehemently scream “bubble.” When King Digital (KING), maker of the popular game Candy Crush, made its public market debut today, investors seemed to have noticed the chatter.
Shares of the Ireland-based company immediately traded down to $19.06, from their market debut at $20.50. The stock recovered slightly mid-day.
Sentiment around the company was difficult to read in the days leading up to the IPO. On one hand, King is a profitable, growing business with a hit game. King Digital’s games are played by 408 million people each month (the vast majority of which are for Candy Crush), and 12 million are paying players.
On the other hand, look at Zynga (ZNGA). Even though King has beat its fellow casual gaming company Zynga on every key metric, too many investors got burned on Zynga’s crash. They’re wary.
The greatest fear is whether King can repeat its breakout success, Candy Crush. Very few game makers are able to replicate their hits. Rovio has yet to repeat the success of Angry Birds, so it has built a giant licensing and franchise business around it, even as the game loses cultural relevance. Zynga hasn’t been able to replicate the success of Farmville (the closest it came was with CityVille, a spin-off).
MORE: On eve of IPO, how does King Digital compare to Zynga?
The chart below shows the rise and fall of Google searches for Farmville, Angry Birds, and Candy Crush. Interest in Candy Crush peaked in August.
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From the NYSE trading floor, King’s IPO listed very quickly, compared to other hot stocks, like Twitter (TWTR). That’s in part because the initial share price, which valued King at more than $7 billion, was slightly aggressive, and so the range of initial bids was not large. Many investors who had bought into the King IPO sold immediately.
With Twitter, pricing took more than an hour, with the price indication updated three or four different times with a higher price before the stock was officially listed. Twitter shares eventually listed at $45.10 per share, almost double the $26 price it had set the night before. King priced its IPO at $22.50 a share and began trading at $2 below that.