Human: I've been told that I have a fungus on my toenail. What is this? Assistant: 
You may be referring to a condition called Onychomycosis, which is caused by a fungal infection of the nail bed. It's not uncommon and can affect up to 10% of the population. The fungus grows in the nail bed and causes thickening and discoloration of the nail. Symptoms include pain and discomfort when wearing shoes, yellow-brown discoloration of the nail, and difficulty removing the nail plate with a file or clipper. Treatment options include antifungal creams, oral medications, and laser therapy.