With Wendy's as a frequent antagonist in social media battles between burger flipping chains, it was cast as the antagonist of this tweet by many. But a quick scan of recent Wendy's tweets doesn't show anything for the King to get salty over. (Plus, Burger King hasn't been shy about slinging mud in that direction previously.) An inquiry about the tweet did not receive a response prior to publication.
The tweet did, however, get a reaction from followers who thought the tweet was a mood or couldn't help but hazard a guess as to what the chain was beefing about internally.