Kamaru Usman claims he would "murder" Conor McGregor after the Irishman demanded a welterweight title shot.
McGregor is currently in the final stages of his recovery from a broken leg and plans to return to sparring next month.
The Irishman could make his cage comeback in the summer - and he wants to challenge 170lb champion Usman.
The Nigerian is pencilled in to face Leon Edwards - but appears willing to take on the Dubliner.
"You guys want a murder scene in the octagon," he tweeted following McGregor's claim.
The Dubliner has fought at welterweight three times in his career, sharing a win and a loss with Nate Diaz before stopping Donald Cerrone inside 40 seconds.
And he told the Mac Life: "“I believe versus Usman for the 170lb title for my comeback is the one I’m eyeballing at the minute.
"I haven’t really said that to no one to be honest, I’ve only been thinking that for the last couple of days because for what cut the weight? I’ve already won the 155lb title, I got myself down to a lightweight frame, but I’m big now.
"I feel big, I feel strong, I feel healthy, I’ve got good energy. I’m coming back after a gruesome injury. I do not want to deplete myself, there should be no need to deplete myself.
"And I feel confident against Usman. A jab happy, sloppy, orthodox wrestler with no submissions whatsoever. What’s he going to do? Where’s the danger here? I don’t see a danger with him.
"His ground-and-pound isn’t strong, plus he’s on the older side. And then plus the world is to be took again. The triple crown. No one’s ever obtained three knockouts in three weight divisions moving up like I have already, but no one’s ever obtained three UFC world titles cross three divisions like I will do also if we make this fight."
Should Conor McGregor be handed a 170lb title shot? Let us know in the comments section below
McGregor is unlikely to be granted his wish but Usman is struggling for challengers to his title.
He has twice beaten Jorge Masvidal and Colby Covington and should he see off Edwards, Usman could turn to McGregor later this year.
In the meantime, the former two-weight world champion could settle his rivalry with Diaz before moving on to a title shot.
"Enough is enough with the disrespect that comes my way," he added. "People are gonna give me my respect for the many facets of my game.
"My fighting style and everything else. I’m gonna waltz right back into a title shot, make no mistake about it. It’s that or I won’t, you know what I mean? It has to be a title shot. What else can it f****** be?
"Now I’m saying that, let’s see how things shake up. There’s plenty of fights. I’m a fighter at the end of the day. I’ll say that, but I’ll probably f****** do anything because I just want to fight and compete.
"But I want that gold belt. I’m going to get that world title that has the Irish tricolor emblazoned on it. I’m the reason that tricolor is on that UFC world title. So I’m eager to get my hands on that belt."
