A prime example of a great compliment you can give to a nice person.
Also a condition for your feet, where literall mushrooms grow between your toes. The Fungus Amungus condition is known to be quite painful.
Fungus Amungus comes from the old latin word "mater tua" which means "greatness to you"
Also it is the inspiration for the popular videogame "Among Us" title.
(if you ever experience symptoms of Fungus Amungus, seek help at your local doctor immediately)
-hey, you have a nice haircut
-thankyou, fungus amungus!
or
-I am sad to inform you that... you have the Fungus Amungus.