They are mythologised as cute and cuddly - but one koala's "very unusual" behaviour has shown the animal's scary side.

The koala gave chase to dairy farmer Ebony Churchill as she fled on a quad bike at a property near Heywood, in western Victoria.

Ms Churchill captured the pursuit on camera and posted it to Facebook, where it has so far garnered more than 25,000 shares and 1.2 million views.

The soundtrack is an odyssey of fear that underlines how this unassuming marsupial can be terrifying when in full flight.