Kid Rock found a new way to make waves at this Sunday’s Billboard Music Awards.

The 42-year-old “All Summer Long” singer is not known for mincing his words, a trait that quickly revealed itself at last night’s Billboard Music Awards show at Las Vegas’ MGM Grand Garden Arena. The rocker took to the stage with a mysterious white mug in tow, and wasted no time in making his thoughts known.

"Let's give it up for people lip-synching under pre-recorded music," he said, before presenting the 2013’s Top Rap Song award to Macklemore and Ryan Lewis for their catchy song “Thrift Shop.” The pointed comment immediately resulted in a social media frenzy, as fans attempted to determine what Kid Rock meant by the lip-synching comment, as well as whether or not it had been directed at a particular artist.

Earlier in the night, R&B star Chris Brown had performed a highly choreographed, physically demanding rendition of his hit song “Fine China,” prompting some fans to suggest that Kid Rock had aimed the barb in his direction. Others suggested that the rocker’s lip-synching comment was meant to mock Selena Gomez’s performance of “Come & Get It.”

Yahoo! Music’s Wendy Geller commented that Kid Rock’s lip-synching jab may have been directed at rap music in general. The accusation isn’t entirely outlandish, considering the genre’s propensity for glossy, auto-tuned tracks that focus as much on production value as they do on traditional vocals.

Still, it seems unlikely that Kid Rock, an artist who became famous for blending the rap and rock genres on songs such as “Bawitdaba,” would bash a type of music that he has personally performed. Regardless of what he meant by his lip-synching comments, fans seem to be united in their quest to ascertain the contents of the singer’s white mug.

Kid Rock’s lip-synching comment wasn’t the only controversy produced by the 2013 Billboard Music Awards. During a performance of his award-winning song “Adorn,” R&B artist Miguel attempted to leap over a group of audience members—accidentally kicking an audience member in the process. Meanwhile, increasingly troubled crooner Justin Bieber was booed during his acceptance speech for Billboard’s Milestone Award.