Luke Bryan just took the Georgia-Florida rivalry to a whole 'nother level ... the country music superstar is now using Tim Tebow's Heisman Trophy to cast a curse on the Gators!!!
Bryan -- a BIG Georgia fan -- revealed Thursday he and his wife won the rights to the trophy for 6 months at a charity auction last year ... donating cash to the Brett Boyer Foundation in exchange for the honor.
The thing is ... Tim waited until this week -- just days before the Gators-Bulldogs game on Saturday -- to deliver the award, and Bryan said he believes something was fishy about the timing of all that.