Musk was apparently infuriated by British diver Vern Unsworth, who stated very publicly that he believed Musk's involvement in the ordeal was simply a public relations stunt. He let off a flurry of tweets, saying the submarine absolutely would work and he would film a video of it going through the cave to prove it. "He had no conception of what the cave passage was like", Unsworth told CNN in an earlier interview.
"The submarine was about 5ft 6 [inches] long, rigid, it wouldn't have gone round corners or any obstacles", the diver explained of the rescue conditions. "It wouldn't have made it the first 50 meters", the British diver added.
He also called it a PR stunt as it wouldn't be able to navigate the complex tunnels of the Tham Luang cave complex, adding Mr Musk was not needed and was asked to leave.
Musk did not take Unsworth's remarks lightly.
"If not true, then I challenge this dude to show final rescue video".
Alexis Sanchez absent as Manchester United head to U.S. for pre-season
Manchester United have signed Shakhtar Donetsk midfielder Fred and FC Porto defender Diogo Dalot in the summer transfer window so far.
Musk also insisted that he was asked to help repeatedly with the rescue and worked with Rick Stanton, another one of the divers who found the boys in the cave, to design the sub. He later went into overdrive to finish the production of a tiny submarine he thought would be useful in the recovery of the Wild Boars soccer team.
Twelve boys and their football coach were rescued from the Tham Luang cave complex last week by an global team after a week-long intense drama.
Musk deleted his tweet thread around 8:30 p.m. Sunday evening, but Unsworth has saved copies.
Musk seems to have been well aware of the blowback, writing that the criticism "has shaken my opinion of many people".
An worldwide team of cave-diving experts rescued the group of 12 teenage boys and their coach last week, after they had been stuck in the cave since June 23.
The children were eventually rescued individually, each accompanied by two divers and navigating dark and tight passageways filled with muddy water and strong currents, as well as oxygen-depleted air.