u/Deep-Cry-5800

I have Cookie Clicker playing in the background while I do things on my computer, and I checked on my garden to find a Shriekbulb growing in the middle of my circle of Elderwort. As you can see in my seed list, I don't have shriekbulb. I checked the garden wiki page, and it says you can only get Shriekbulb from Duketater. Does anyone know how this happened?