Backstory: back during the ice storm, I went outside and snapped off a little plant to bring it inside and admire its icy encasement. Lloyd was working in the basement, so I showed it to him, then hung it in the laundry* sink to thaw.
I forgot about it.
Second part of backstory: I hang up socks above the laundry area.
Apparently, a while back, one of my socks fell in the sink. Remember that the cats like to get water there? Well, the little dry seeds from the plant must have fallen in the sink, too, and some of its seeds have sprouted….
* No laundry is done in that sink.