What happens when the two biggest stars in fighting can't actually fight each other? We get them insulting each other in public—trash talking because the dream matchup won't happen.Floyd Mayweather took some shots at Conor McGregor Wednesday, escalating the non-feud on Instagram. First, he put out a video of McGregor tapping out in his March loss to Nate Diaz and wrote: "CAPTION THIS! Best caption wins $10,000.00." The video ends with a fade to black and a picture of Mayweather pointing and laughing followed by a message: "49-0 vs. CONNOR THE NOTORIOUS QUITTER." Mayweather didn't even have enough respect for McGregor to spell his name right.Then he went at McGregor again. Mayweather went on Instagram Live and called him "Conor McTapout" and had a fake interview with some guy making fun of McGregor's Irish nationality, according to ESPN. He also called McGregor some more not so nice words, says TMZ.We'll see how McGregor retaliates. He's acquired a boxing license in California and is taking a break from UFC. Nobody seems to think this fight could actually happen but it doesn't mean we can't enjoy a wrestling-style ramp-up for it. Just let them into a ring and let them shoot.Or maybe we can settle this in the only ring they have in common.