The 20-year-old's high school friend, Quinn McPherson, had been learning mixed martial arts and - after an evening and morning drinking vodka, beer and doing lines of cocaine - put Mr Robinson into a chokehold.
While on FaceTime to friends in Adelaide, about 9am on May 13, 2023, McPherson said "watch this guys" and began play fighting with Mr Robinson in a Melbourne apartment, the Supreme Court was told on Monday.
McPherson wrapped his arms around Mr Robinson's neck, placing him into a chokehold for several minutes, and stopped after noticing he was turning blue.
"(We were) play fighting, mucking around, having a bit of fun and that's when I noticed his lips were blue," McPherson would later tell police.
"We're good mates, so obviously we don't want to hurt each other."
Two other friends came into the room and saw Mr Robinson hanging off the side of a bed with a blue face.
McPherson told them to call an ambulance and they tried to perform CPR until paramedics arrived.
Mr Robinson could not be resuscitated and was declared dead by paramedics at 10.23am.
An autopsy found his cause of death to be undetermined.
McPherson, a tradie from South Australia, was initially charged with manslaughter, but pleaded guilty to a lesser charge of conduct endangering life at a pre-sentence hearing on Monday.
He is on bail, allowing him to return home to Adelaide between hearings.
McPherson's defence team said the charge reflected he would not be sentenced for causing Mr Robinson's death.
The maximum prison term for the offence is 10 years, but McPherson will likely to walk free on a community corrections order.
Mr Robinson's family gave emotional statements to the court about the impact of his death.
His sister Grace, between tears, stood and looked at McPherson in the court dock and said: "I hope, Quinn, that you think about this every day like we have to."
"It's definitely not fair on Alex to have his life stolen from him," she told the court.
His mother Natalie Elliott said she'll "never be certain" McPherson's actions didn't take away her son's life.
"Not knowing what happened in my son's final moments keeps me up at night," she told the court.
"I still don't know what happened to Alex and I don't know if I ever will."
Calvin Quaziz, who was on the trip, said the deadly events constantly replayed in his head like a documentary.
"No one should have to see their friend laying lifelessly on the floor," his said in a statement read to court.
"I wouldn't wish this upon anyone, not even my worst enemy."
Justice James Elliott said the case was unusual as he asked the court to spend one minute in silence to remember Mr Robinson.
Defence barrister Paul Smallwood acknowledged the "unimaginable sorrow and anguish" Mr Robinson's loved ones were experiencing and noted his client's actions before the death were "dangerous".
He said the tragic circumstances of the offending reflected the dangers of young men imitating what they "see on their screens" when watching UFC fighting.Â
He asked for McPherson to be given a community corrections order, with community work and rehabilitation conditions, due to his "significant remorse", that he was aged 19 at the time, and his guilty plea.
Prosecutor Nadia Kaddeche agreed McPherson should serve a community order instead of prison time.
Justice Elliott said he hoped to sentence McPherson on March 27.
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