Harmonia axyridis is a large lady beetle or ladybug species that is most commonly known as the harlequin, multicoloured Asian, or Asian lady beetle. This is one of the most variable species in the world, with an exceptionally wide range of colour forms. It is native to eastern Asia, but has been artificially introduced to North America and Europe to control aphids and scale insects. It is now common, well known, and spreading in those regions, and has also established in Africa and widely across South America. This species is conspicuous in North America, where it may locally be known as the Halloween beetle, as it often invades homes during October to overwinter.