MORRISVILLE, Vt. – Forget David and Goliath. This fight’s between Matt and Monster.

The maker of Monster energy drinks has taken aim at a Vermont brewery that sells a beer called “The Vermonster,” ordering it to stop selling, advertising and promoting the craft brew because it could confuse consumers.

The energy drink-maker, Hansen Beverage Co., wants tiny Rock Art Brewery to stop using the name “Vermonster” on the barley brew and to compensate it for its attorneys’ fees.

Matt Nadeau, who owns the brewery with his wife, Renee, says he’s been told by five trademark attorneys that the law is probably on his side, but that proving it through lengthy litigation could bankrupt him.

“This is just about principle,” said Nadeau, 43. “Corporate America can’t be allowed to do this, in this day and age. It’s just not right.”

The beer is made at Rock Art’s small warehouse brewery in Morrisville, which employs seven people, and is sold in 22-ounce brown glass bottles. It hit the market in 2007, and is now sold in Vermont, Massachusetts, Pennsylvania, New Jersey, Connecticut and Arizona.

Based in Corona, Calif., Hansen sold more than $1 billion worth of Monster drinks last year. The products carry a distinctive three-line logo designed to look like a claw mark.

“A lifestyle in a can,” its Web site proclaims.

The dispute began last month, when a lawyer for Hansen Beverage sent an e-mail message to Nadeau’s attorneys saying the brewer would “undoubtedly create a likelihood of confusion and/or dilute” Hansen’s trademark.

The Hansen lawyer who wrote the e-mail, Diane M. Reed, declined to comment. A telephone message left for a Hansen spokeswoman wasn’t returned.

Nadeau contacted Reed to say the products are in two different markets – beer and energy drinks – and offered to surrender any rights to use the name on an energy drink. According to Nadeau, Reed said that’s not Hansen’s concern, but that Hansen wants to enter the alcoholic beverage market.

“I said ‘Too bad, I’m already here.’ I’ve been here. And I’m already brewing beer,” Nadeau said.

Such warning letters aren’t unusual in trademark disputes.

“The way the law is arranged, the holder of a trademark has to be very aggressive in defending it, even when it’s overreaching,” said Douglas Riley, Nadeau’s trademark attorney. “If you miss a legitimate infringement, people will point out in later years that you weren’t defending your properties. You can lose it if you don’t defend it, so you err on the side of caution.”