A West Coast brewery owned by Anheuser-Busch’s parent company is demanding that a Brewer beermaker change the name of its signature IPA.

10 Barrel Brewing in Bend, Oregon, sent a letter to Mason’s Brewing Co. owner Chris Morley, demanding his brewery stop using the name “Hipster Apocalypse” for its flagship India Pale Ale. The Oregon brewery has brewed an “ Apocalypse IPA” since 2009.

Morley, who was in the process of filing for a trademark when 10 Barrel contested the name, said Wednesday he plans to challenge the request, even if it means spending thousands of dollars.

“I’m not backing down. It’s our most popular beer,” he said. “This is another great example of a corporation trying to keep the little guy down.”

But it could be an uphill battle. In 2014, 10 Barrel was purchased by beer titan AB InBev, owner of Budweiser, Corona and Stella Artois. About a decade old, 10 Barrel Brewing Co. also has pubs in Portland, Oregon, Idaho, California and Colorado. Representatives from 10 Barrel and AB InBev did not respond to calls or emails for comment.

10 Barrel Brewing has claimed that Mason’s has violated state and federal trademark laws by using the word “Apocalypse,” according to the letter from 10 Barrel’s California-based attorney.

The Oregon company wants Morley to withdraw his pending trademark application, claiming it has intellectual property rights to the name “Apocalypse,” according to an August letter sent to Morley’s lawyer.

“To be clear, 10 Barrel is not seeking to interfere with your client or prevent the sales of any particular style of beer,” the letter read. “But it cannot allow Mason’s to sell beer that capitalizes off the goodwill 10 Barrel has generated in its “Apocalypse IPA” beer, or that otherwise undermines 10 Barrel’s trademark rights.”

Because the Oregon brewery “cannot control the goodwill in its valuable Apocalypse IPA mark, and such goodwill would be damaged by any consumers having a negative experience with your client’s ‘Hipster Apocalypse’ beer and attributing it to 10 Barrel.”

Mason’s, which has been in business for less than two years, produces approximately 2,500 barrels annually and is also currently distributed in Massachusetts, Morley said.

“Apocalypse” isn’t an uncommon name in the beer world, Morley said. Accessing the “Untappd” beer app on his smart phone, Morley pulled up at least 10 other beers across the country with “Apocalypse” in the name.

Other Maine breweries have fought similar battles before. Shipyard Brewing, in Portland, sued Missouri-based Longboat Brewing Co. in May over the name of its “Shiphead” beer.

If the issue is taken to court, it could take tens of thousands of dollars and likely more than a year to settle, Morley said. But so far, he’s using the dispute as a way to market his brewery, in good fun.

“If I’m going to spend a lot of money, I might as well have fun with it,” he said.