McGregor (22-4) took to social media on Monday to offer his thoughts on the 155-pound landscape. A former two-weight champion, McGregor demanded to fight Gaethje next. Gaethje is coming off a fifth-round TKO of Tony Ferguson at UFC 249, which took place Saturday without a crowd present because of the coronavirus pandemic.
Gaethje is expected to face undisputed champion Khabib Nurmagomedov in a unification bout next.
"The fans make the sport!" McGregor wrote on Twitter. "Watching the other night, I was against going in without them. But it will be my f---ing pleasure to display the power I possess with zero background noise for them. It's me and Justin next as khabib is the biggest bottle fighter in the game. Guarantee it.
"Justin, there is no danger in a man that hugs legs, we all know. Try and dance around what the real threat is here all you want. I am going to f---ing butcher you. Your teeth. I'm going to put them on a f---ing necklace. Speak on my skills as a father? You are f---ing dead."
McGregor might have been referring to a September 2019 tweet from Gaethje in which Gaethje called McGregor a "s--- human, father and husband."
McGregor, 31, also praised Ferguson's toughness in his TKO loss to Gaethje. It was Ferguson's first loss in 13 appearances.
Ali Abdelaziz, who manages both Nurmagomedov and Gaethje and has frequently been a target of McGregor's criticisms, told ESPN that there is no chance McGregor would jump the line to a title fight.
"Right now is the holy month of Ramadan, so I cannot talk about anyone out of respect of Ramadan," Abdelaziz said. "He had a chance to fight Justin in January, and he picked [Donald "Cowboy" Cerrone] instead. He picked the easier fight. Now, the two kings of the division will fight. Maybe Conor can fight someone in the co-main event."
McGregor's social media outburst came just days after he told Nate Diaz to "sign the contract" in a comment on Instagram. UFC president Dana White has confirmed that McGregor is interested in fighting sometime this summer, but he said they have not discussed a specific date or opponent.
McGregor posted a follow-up tweet later Monday, writing "See you in July" with Ireland, U.S. and clover emojis.