Police in Victoria state believe the "bum bandit" was with two others when they did the "full moon" during a break-in at a community centre in the city of Wodonga over the weekend.
"I've never seen anyone's bum print turn up at a crime scene," Detective Sergeant Graeme Simpfendorfer told AFP on Tuesday.
"The crime scene officer who was dusting for prints... with every stroke, he was thinking, 'what have we got here?'.
"He came and told us and just said, 'I've got a butt print. It's certainly not just from a pair of jeans or tracksuit pants. This guy's pants down.'
"It was quite obvious to him and when we looked at it, it's obviously quite clear that he's actually gone the full moon."
Simpfendorfer said the trio, believed to be aged in their late teens or early 20s, stole a television and sprayed a fire extinguisher around the centre.
He added that while the bum print would not help investigators crack the case, there were other clues to help get to the bottom of what went on.
"We don't obviously take bum prints," he said.
"But we've certainly got other forensic evidence there that will be on our system and we'll be able to identify who they are and hopefully... get to the bottom of why this person decided to (go) pants down and leave an impression."