A cease and desist letter from Domino’s Pizza hasn’t deterred a small pizza chain from continuing to challenge the national company in its advertising.

In June, Toppers Pizza opened a new store in Duluth, MN. To celebrate the event, the company ran an ad featuring a Domino’s truck delivering dough to one of its stores next to an image of a Toppers worker carrying a bag of flour. “Not making dough in-house? What.The.Truck.” the flyer stated.

Domino’s responded with a cease and desist letter, but Toppers wasn’t backing down. In a blog post, Toppers founder Scott Gittrich—who worked for Domino’s for roughly eight years before starting his own pizza company in 1991—vowed to keep up the effort to differentiate the growing brand.

“Excuse me for telling the truth!” he responded. “This truth: Dominos [sic] makes their dough in factories and ships it to their stores several times a month. WHAT THE TRUCK, right?!”

Toppers also shared a recent Facebook picture of a Domino’s 18-wheeler pulling up in front of a store with the added message: “So, everyone knows Domino’s drives their dough around the country & through communities in heavy semi-trucks, vs. making their dough fresh in house … #WhatTheTruck.”

More “Us vs. Them” ads are in the works, Gittrich promised. “We’ve got to make our creative work harder, let’s face it,” he told AdAge. “We’re fighting these people that are running TV ads every eight minutes or something.”

To read Gittrich’s blog post about the advertising battle, click here.

Why it matters: While companies have certainly used advertising to directly target a competitor before (think Apple’s Mac vs. PC television commercials), Toppers also has an underdog angle, with just 86 stores and sales of $61.2 million in 2017 as compared with Domino’s 5,500 locations in the United States and sales reaching almost $5.93 billion last year.