Best to leave the koalas alone. Image: Shirlaine Forrest/WireImage Don’t mess with the koalas, Katy Perry. The pop star faced criticism for telling her pet dog Nugget “let’s go chase some koalas” in an ad for Australian department store chain Myer. But one veterinarian wasn’t cool with the koala, saying it reverses efforts to stop dogs coming into contact with the marsupial. SEE ALSO: Jellybean the joey has just left his mother’s pouch and he can’t stop bouncing “Perry is a role model to so many young people, and this just destroys all the good work we do to try […]