Where Did That Come From?

I looked in my beans today and I discovered a half dozen caladium shoots coming up! I had a caladium last summer. After it died at the end of the summer I dug through the dirt looking for whatever might be left that I could see if I could save and resurrect this year, but I found nothing. I've got zucchini planted in that pot now. I guess at some point I must have used some of the old soil out of it in the pot I planted the beans in. That's the only way I can figure the caladium would suddenly reappear. Weird.