BEST FEUD EVER?
An awesome new twist in the Dana White vs. John Oliver feud -- Dana is now selling UF-SEA t-shirts as John suggested ... with all of the proceeds going to one of John's favorite charities.
OK, some brief backstory ...
Over the past few months, the "Last Week Tonight" host has been clowning White over the name "Fight Island" -- saying White would have been better off calling it "UF-Sea."
"He was making fun of Fight Island," White says .