There’s a big beef between McDonald’s and Wendy’s.

Wendy’s just dissed McDonald’s announcement that by mid-2018 the Quarter Pounders at most of its restaurants would be made from fresh beef. “So you’ll still use frozen beef in MOST of your budgets in ALL of your restaurants? Asking for a friend,” Wendy’s wrote on Twitter.

They’re not the only ones dissing their competitors on Twitter. Delta swiped at United just with a pro-leggings post. The competing airline has been slammed for banning two girls wearing stretch pants from a flight on Sunday.

“Flying Delta means comfort. (That means you can wear your leggings.)” said the burn from Delta’s official Twitter account on Monday – complete with a winking face emoji.

Customers ate it up. It’s been retweeted 26,000 times, and scored 89,000 likes and counting.

It’s the latest brand building buzz by tweeting not-so-subtle digs at rivals.

When Wendy’s tweeted a snap of a tray loaded with chicken nuggets, a burger, fries and a soda captioned as “The 4 for $4 meal,” Burger King shot back with pic of a five-piece meal and the dig, “5 for $4, because 5 is better than 4.”

Merriam-Webster nailed it with this tweet against rival Dictionary.com. The latter posted a pic of a woman holding a cup of black coffee with the “Pemberly by the Sea” quote, “I like my coffee with cream and my literature with optimism.”

Without missing a beat, Merriam-Webster tweeted back “There’s no cream in that coffee.”

Merriam-Webster has also gleefully called out President Trump’s colorful language, tweeting that the world “bigly” exists, but “deproximately” and “braggadocious” do not.

Or how about this 2012 gem, when Old Spice teased Taco’ Bell’s “fire sauce” for not containing any real fire. The taco chain tweeted back, “Is your deodorant made with really old spices?”

These punchy posts don’t always work, though. Denny’s made customers feel a little queasy with a tweet about eating babies after Beyonce announced she was pregnant with twins.

“Wow, bey has TWO buns in the oven! that’s just an expression by the way. please don’t eat those buns. they are babies,” it posted.

#fail