Tyson Fury has promised to retire in his corner if Anthony Joshua can withstand three rounds inside the ring with him.
The pair are preparing for an all-British showdown to determine heavyweight's undisputed champion with the WBA, WBC, IBF and WBO titles on the line.
Fury is confident he can finish the contest - which is likely to occur in late July or early August - within the first nine minutes and has volunteered to quit on his stool if Joshua hears the bell for the fourth round.
"While I'm on a rant I may as well call out one more person: a big, useless dosser, not a real fighting man, a hype job, bodybuild, cross-fit, big, ugly s***house, that's Anthony Joshua," Fury said in a video message on Twitter.
"AJ, if you're out there, let's make this fight happen you big dosser. You big s***house bum dosser, I'll smash your face in and there's not one thing you can do about it. Prove me wrong, sucker, prove me wrong, I'm number one.
"If you go past three rounds with me, I'll quit in the corner because that's how confident I'm taking you cold out within the first two or three rounds. Out like a light switch."
Fury also took aim at mixed martial arts star Francis Ngannou, telling the UFC heavyweight champion: "Look, you want some of this Gypsy King money? You know where to come and find it.
"You want some of this Gypsy King power? I'll give it to you. Any time, any place, anywhere, seven days a week and twice on a Sunday."