While riding on your scooter, you grow a mustache on top of the mustache you already have in order to surpass the people around you. You're in a scooter race and your mustache is the only thing keeping you in the lead, but someone else has a mustache too! So you grow another mustache to surpass them once again!
Suddenly, something else manages to surpass you all. It's a car (か)! A car with two mustaches is also riding on a scooter and going way faster than you.
Currently there are no similar looking kanji which exist in the WaniKani learning system