These are fairly common mushrooms that pop up in
various indoor plantings, as well as outdoors in
some temperate areas.

I had a couple (okay, about 10!) of those bright yellow
mushrooms pop up in one of my pots here on the Windward
side of Oahu. I thought it was from overwatering and cut
back on the watering for a while until they died. It
wouldn't have hurt to let them grow? The plant was doing
okay and wasn't showing signs of overwatering, other than
the mushrooms.

Tracey