A teenager discussed packing a kangaroo with explosives, painting it with the ISIS symbol and setting it loose on police, according to prosecutors.
Sevdet Besim, 19, is accused of plotting a terror attack in Melbourne on Anzac Day — an annual public commemoration of Australia's war dead.
Besim denied four charges of planning a terrorist act during a court appearance on Thursday, the Melbourne Age newspaper reported.
Prosecutors also accuse Besim of communicating with a teenager overseas, as well as planning to run over and behead a police officer on Anzac Day, it said.
A prosecution summary presented to Melbourne Magistrates Court included an account of alleged communication between the two teenagers, including a conversation about using a kangaroo as part of an attack, the Australian Broadcasting Corp. (ABC) reported.
"The conversation continues with Besim detailing what he did that day and they have a general discussion around animals and wildlife in Australia including a suggestion that a kangaroo could be packed with C4 explosive, painted with the [ISIS] symbol and set loose on police officers," the prosecution summary said, according to the ABC.
Copies of the summary document were not available early Thursday on the court's website.
At the time of Besim's arrest in April, police said the alleged Anzac Day plotters had links to Numan Haider, an 18-year-old who stabbed two Melbourne police officers in 2014 and was subsequently shot dead.
Anzac Day is the annual April 25 commemoration of the 1915 Gallipoli landings — the first major military action fought by the Australian and New Zealand Army Corps during World War I.