YouTube star MrBeast spoke out on grooming allegations made against his longtime collaborator, Kris Tyson, in a message posted Wednesday to Twitter. MrBeast, whose real name is Jimmy Donaldson, penned a caption after a social media user alleged Tyson engaged in explicit exchanges and grooming methods online. “Over the last few days, I’ve become aware of the serious allegations of Ava Tyson’s behavior online and I am disgusted and opposed to such unacceptable acts,” MrBeast wrote in his statement. SYDNEY, AUSTRALIA – JUNE 26: Mr Beast, a.k.a Jimmy Donaldson speaks to the media during the MrBeas…