Yeah, Tyson came into the club in which Cormier and his Gold's posse worked (Flex, etc.), and slapped Chris upside the back of his head. When Cormier turned around, like, What the ... , he saw Iron Mike and paused, and then almost immediately Mike flashed a great big grin and said something to the effect of, "C'mon! You're a big boy. You can take it." Apparently the tone was good-natured.
I spoke with Chris about this not long after it happened.
He told me he was happy Tyson was playing around because he wouldn't have wanted to get into it with Mike.
Let's not forget Cormier had already broken his hand working that club, as well, getting into it with goofy-bastard customers.