There's a billboard advertising pizza in Mounds View, Minnesota, that has been working. A billboard that works, is one that grabs attention and conveys a message.The kind of message that entices consumers to spend their money on the advertised product.

This story, by the way, is not a lesson on successful billboards. It's a story about a billboard that maybe went to far. Oh, it's working, but working way beyond good. It's actually causing problems.

The big sign is on U.S. 10 near the Interstate 35W junction. It's the convenience store chain Casey's that has the display. They are advertising their pizza.

The picture of the monster pepperoni pizza is enough to make you look and perhaps make you hungry. But where things go wild, is when you see what appears to be steam coming off the pizza, suggesting that it's piping hot.

The steam is actually a hidden fog machine. But several motorists thought the sign was on fire and called police. After being flooded with calls, authorities have asked to have the fog machine turned off for now.

Take a look at the quick video and see the steam appearing fog: