It's a lunatic ninja coming through the window.

So thought Beat Ettlin when he first awoke to the bouncing on his bed.

When a dark intruder smashed through his bedroom window and repeatedly bounced on his bed, Beat Ettlin was initially relieved to discover it was a kangaroo.

"My initial thought when I was half awake was: it's a lunatic ninja coming through the window," the 42-year-old told The Associated Press on Monday. "It seems about as likely as a kangaroo breaking in."

Some men dream of naked women, but Beat dreams of lunatic ninjas.

But his relief was short-lived. Moments later, he heard his 10-year-old son Leighton Beman scream from bed: "There's a 'roo in my room!"

"I thought: This can be really dangerous for the whole family now," Ettlin said.

The extraordinary ordeal for the family of four began at 2 a.m. Sunday in their house in the upmarket Canberra suburb of Garran.

Ettlin, a chef originally from the Swiss city of Stans, wrestled the thrashing and bleeding 90 pound marsupial out the front door.

"I had just my Bonds undies on. I felt vulnerable," he said, referring to a popular Australian underwear brand.

I wonder if he is trying to get endorsement money. But saying you are vulnerable in your Bonds undies is not going to do it for the company. Perhaps you should claim that they boosted your courage.

The kangaroo, which Ettlin said was around his height, 5 foot 9 inches, left a trail of blood through the house and claw gouges in the wooden frame of his bed.

Ettlin, who was left wearing just his shredded underpants and with scratch marks on his leg and buttocks, described himself as "lucky."

His wife doesn't consider herself lucky though.

The kangaroo vanished into a nearby forest from where it likely came. The family reported the intrusion to police and to wildlife authorities.

The animal hopped a fence to reach the family's backyard. The family suspects it felt trapped and tried to escape the yard through the bedroom window which is about 5 feet above the ground. It was likely cut by the broken glass.

Kangaroos rarely harm humans, but when they do, it is usually because they feel cornered. They have been known to disembowel people with the claws of their powerful hind legs.

Although it had been a dangerous and harrowing experience, Ettlin's wife could see a funny side to the family's unusual predicament.

"I think he's a hero: a hero in Bonds undies," Verity Beman, 39, said of her husband.

Kangaroos have powerful hind legs and short, thumbless forelimbs. They can travel at speeds up to 30 miles per hour and can leap some 30 feet. Kangaroos use their long tails for balancing. Their bodies are covered in thick, coarse, woolly hair that can be shades of gray, brown or red.

Red and gray kangaroos stand between five and six feet tall. Most weigh between 50 and 120 pounds, though some can reach 200 pounds. Female kangaroos are generally smaller than males of the same species.

When cornered or it thinks itself cornered, a kangaroo can become deadly. But so can many animals when in that position.

I know that this isn't really a very funny story, but I could just imagine what it must have been like to wake up with a kangaroo jumping on your bed.