A mushroom by any other name...

Leucocoprinus birnbaumii.
Yellow parasol.
Plantpot dapperling.
Yellow pleated parasol.
Or my personal favorite, lemon-yellow lepiota (after its old scientific name).

 

Whichever name you so choose, these guys would still be yellow, dusty-looking, and living with my potted Pentas. I was freaked out by them when they first sprouted up out of nowhere, but I think they've grown on me (figuratively AND literally).