Keith Thurman branded Manny Pacquiao a "bunny rabbit" as the pair faced off ahead of their world title clash.
The rivals will touch gloves in Las Vegas on July 20 in what promises to be a thrilling welterweight clash.
And Thurman has resorted to bizarre trash talk in the build-up.
He said: "It's a blessing to be on this stage and have a fight of this magnitude. I'm an all-American fighter, an all-American champion and come July 20, I'm going to stay champion.
"Manny is a world class fighter. He's a gentleman inside and outside of the ring. I look forward to trading punches with a living legend. But one thing's for sure, he's not walking away with my title.
"All Manny does is hop around in the ring. I'm not going to lose to a bunny rabbit. He's not Tupac, but he does a little hip hop and he's not going to stop until he gets dropped.
"Manny is a world class fighter, not a world class boxer. I'm going to trip him up in the ring and he won't know what direction to turn to. I know who I am as a fighter, and it will be proven come July 20."
Pacquiao, meanwhile, dismissed claims he is over the hill at 40.
"It's easy for my opponents to talk before the fight, and I'm used to everything they say," he said. "But when we get to the ring, it changes, and it will change on July 20.
"I chose Keith Thurman because he's a great fighter, he's undefeated and because we can give a good fight to the fans. I want to make the fans happy on that night and show that I can still go toe-to-toe with any opponent.
"He said he's young, but we'll see who looks young in the ring on July 20. I'm going to let my fists say everything for me.
"We will work hard in training camp like always for this fight. We're not going to take Keith Thurman lightly or underestimate him. He's a world champion. I'm thankful for what he's been saying, because it's giving me motivation to prove that at 40-years-old, I feel 29."
