1. Ear mites
Ear mites are a specific type of mites that can be found in the ear canal of animals (it is the most frequent cause of ear infections among cats) and humans. Although they are somewhat rare in humans, it is possible that these tiny beings can make their way into human ears while the person is petting their cat or dog.
Sharing earbuds with someone who has ear mites inside their ear canal might be really dangerous since earphones can easily function as a vehicle of transmission. Some species of mites can function as a vector for disease transmission and cause allergenic disease. However, you don’t need to worry too much about this since the vast majority of mite species are actually harmless to humans.