A father, known by the pseudonym ACF, told the anti-Semitism probe his son had been uncharacteristically glued to his phone since the attack by terror group Hamas on Israel on October 7, 2023.
The boy, who was seven at the time, was told by friends that his "Israelian" family should be killed by the terrorist organisation.
"I hope Hamas bombs your fat arses" one post said.
"You should kill yourself," said another.
The experiences mirrored that of another family, whose daughters were subjected to relentless crude messages and videos from other children because they were Jewish.
The eldest daughter, who used a wheelchair at the time, was depicted in an AI-generated video struggling to swim through liquid.
In another video, the words "g@s inh@l3r" were written below an image of the girl when she was in year four.
'She was devastated," the girl's mother said. "The whole school year knew about it."
The anti-Semitism royal commission resumed in public view on Monday after a behind-closed-doors stretch focused on security issues.
For the next fortnight, commissioners will be trained on the role of media - particularly the ABC and SBS - and the nature, prevalence and drivers of anti-Semitism and other hate speech on social media.
Labor MP Josh Burns will appear first on Tuesday to speak about his experience as a Jewish Australian.
Mr Burns, who represents the inner Melbourne seat of Macnamara, previously said the period since October 7 had been one of the hardest in his life.
He is expected to tell the commission that his office has received thousands of threats since that time, and that public engagements have been amended due to fear for his safety.
Ben Adler, a prominent musician with Sydney Youth Orchestra, is also expected to front the commission.
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