The veteran prime minister brought Giora Ezra, 63, to a press briefing on Monday in a bid to dismiss accusations his Likud party has deployed an army of internet bots to help get him reelected.
"Say, Giora, are you a real person? Are you a robot?" Netanyahu asked with a smile.
"Giora says what he thinks, nobody is operating him, it's one huge lie."
The publicity stunt came after an Israeli cyber watchdog reported a network of fake online accounts backing Netanyahu and slandering opponents ahead of next week's general election.
"I woke up this morning and discovered that I'm a robot," Ezra said as Netanyahu chuckled.
"I write what I write from my heart," he said.
But the premier's attempt to present living evidence of his popular support after widespread coverage of the allegations soon appeared to backfire as a spotlight was shone on Ezra's online activities.
It turned out Ezra, who writes on Twitter under the handle "Captain George", has a rich history of abusive posts against Netanyahu's opponents and journalists, including homophobic slurs.
'A mistake'
Soon after his internet personality was unveiled, it became apparent Ezra was much more than just a vociferous Netanyahu supporter.
Benny Gantz, Netanyahu's main challenger, needed "to see a psychiatrist", Ezra had tweeted.
"Captain George" insinuated that there was embarrassing sexual content on Gantz's phone, which was hacked last year.
Rabbi Meir Kahane, founder of a racist party that was banned from Israeli politics but still inspired extremists decades after his assassination was "right all the way", he also posted.
And in addition Ezra employed a series of homophobic slurs in his tweets.
Netanyahu's opponents were quick to play up what many saw as odious online statements.
Zvi Hauser, a member of Gantz's Blue and White alliance, asked on Twitter if "sewage workers" got to visit prime ministers in other country's in a joke about his perceived foulest opinions.
A spokesman for the Likud did not respond to AFP queries on Ezra.
But party member Yoav Kisch said it should have checked out "Captain George" and his history of tweets before presenting him to the public.
"It was a mistake," Kisch told army radio.
Yuval Karni, a political reporter for Yediot Aharonot, one of the first outlets to publish the report on fake online accounts, had another take on "Captain George".
"It would have been better if he were a bot," Karni wrote on Twitter.
Follow us on Twitter: @The_NewArab