Call him "P.T. Musk," Cramer said on "Squawk Box."
"I just keep finding it's a three-ring circus with the guy. It's kind of annoying but he's exciting," added Cramer. "He's P.T. Barnum. P.T. Barnum packed the seats."
Barnum's exploits in the mid-to-late 1800s, as the master promoter of what became the Ringling Bros. and Barnum & Bailey Circus, were fictionalized in the 2017 blockbuster "The Greatest Showman," starring Hugh Jackman. Barnum was also remembered for hoaxes and pranks.
Tesla did not immediately respond to CNBC's request for comment about the comparison.
Cramer's remarks came as Musk's most recent proclamations are being put under the microscope.
On Monday, in Palo Alto, California, Musk told an audience at an autonomous-driving showcase that some 1 million of the automaker's robotaxis, with no human drivers, would hit U.S. markets next year. Musk said he was confident in his prediction. However, his forecasts have missed the mark in the past.
Cramer said Musk and Tesla's claims, in particular that its new data chips can potentially perform seven times better than a competing product from Nvidia, put the CEO's "credibility" into question. Nvidia later said in a statement that Tesla misstated details about its chips.
Cramer, host of "Mad Money," has been critical of Musk ever since the CEO's take-private tweet on Aug. 7 stunned the financial community and Washington regulators. Musk eventually abandoned the idea on Aug. 24. At the time, Cramer said Musk's "stunts" were ill-advised, and recommend the board put Musk on medical leave. Cramer later contended that Musk should be removed as CEO of the company.
Last week, Musk and the Securities and Exchange Commission asked for a one-week delay to resolve their latest dispute, stemming from last year's settlement over that take-private tweet.