A teenager faces life in prison for plotting to behead a police officer in a terror attack on Anzac Day in Melbourne.
Sevdet Ramadan Besim planned to run the officer over, behead him with a knife and then go on a violent rampage that would end in his own death.
The 19-year-old chose Anzac Day last year to "make sure the dogs remember this as well as there fallen heros (sic)".
Besim wanted to attack Australia's authority because it would show weakness and put fear into the general population, police have said.
The Hallam teenager was due to face a trial in the Victorian Supreme Court next month, but pleaded guilty to a single terror charge on Thursday.
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The offence - doing acts in preparation or planning for a terrorist act - carries a maximum sentence of life in prison.
Besim said he was "ready to fight these dogs on there (sic) doorstep" in online communications with a person overseas.
"I'd love to take out some cops."
"I was gonna meet with them then take some heads ahaha."
The pair also suggested a kangaroo could be packed with explosives, painted with "the IS symbol" and set loose on officers.
While police did not go into details of the symbol, the image mostly closely linked to Islamic State is the Black Banner or Standard.
It's not suggested the kangaroo discussion was linked to Anzac Day, or any other target.
Besim has been in custody since April 18 last year when 200 heavily armed officers swooped on the city's southeast, arresting five teens and seizing knives and swords.
Besim admits planning his attack from mid-March to mid-April, including researching Anzac Day services in Melbourne and Dandenong.
A "Rambo" knife with a 40cm blade and a tactical knife were found in Besim's car.
Police have said he was motivated by an extremist ideology and had expressed support for proscribed terrorist organisations, particularly IS, which adopts a radical interpretation of Islam.
The teenager had written a "martyrdom" note and had a pledge to the leader of IS.
His note explained his terror plans, quoted from the Koran and gave his family instructions on how to set up his grave, a court heard last year.
He told his overseas associate: "I feel like a young kid with a ticket to disney world cant wait ahahah. Yeh (sic) i wanna make sure i get shot to. Not b4 i take out at least 1."
Besim had an "idea" to storm the Australian Federal Police headquarters in Melbourne.
He pleaded not guilty to four terror-related charges in January and was committed to stand trial.
Only one remains after his last-minute admission before planned pre-trial legal argument on Thursday.
Besim will front a plea hearing on August 1.
