known as the red-headed mouse spider (Missulena occatoria) is a species of spider found in Southern Australia, from open forest to desert shrubland. It is the largest (females up to 24 mm, males up to 12 mm) and most widely distributed Missulena species, because the spiderlings are wind-dispersed (ballooning). Normally this only occurs with araneomorph spiders, mygalomorph spiders normally disperse by walking. Missulena venom may be very toxic, but few cases of serious envenomation have been recorded. Most recorded bites only caused minor effects, with Australian funnel-web spider antivenom having proved effective as a treatment.