The Chionarctia nivea has a downright frightening set of inflatable appendages known as androconial organs, which the male moth uses to disperse pheromones, thereby attracting attention from the ladies. (Many other moths have these, too.)
A YouTuber captured the bizarre process on video, inflating the organs in a deceased moth with a pipette. Wired hastens to point out this isn't a moth penis (that comes later in the process), but more like a set of "inflatable moth butt featherdusters."
According to The Journal of Insect Science, the so-called "coremata" or "hair-pencils" at the end of the inflated appendages disperse a pheromone to signal availability to female moths. The pheromone is believed to vary in strength depending on how much of a particular type of plant chemical (pyrrolizidine alkaloids, if that means anything to you) the moth ate during its larval stage, with more chemicals meaning larger coremata, stronger pheromones and, therefore, greater likelihood of mating.
WATCH the moth's inflatable appendages in action, above.