Fungous can mean the same as fungal, that is derived from, or caused by, a fungus (and those can be things as various as the smell of dry rot, mushroom ketchup, St Vitus' Dance, or the holes in bread). But it has another meaning.
Something fungous appears suddenly, spreads itself all over the place, and then disappears.
So that's practically all TV talent contest winners, then; and to those we can add most youth slang, and, I should imagine, fidget spinners:
photo by BlueAvocado
(Fidget spinners? Well, they...sit on your finger and spin. They are said, though without, as far as I can see, any evidence whatsoever, to aid concentration.
There are videos of fidget spinners in action on YouTube, if you're interested, but I'm afraid I lost the will to live before I got round to choosing one to upload.)
Spot the Frippet: something fungous. This word comes from fungus, which is the Latin for mushroom. It's probably something to do with the Greek spongos, sponge.