What was the strangest plant that has grown on your property, that you didn't plant?

My mother-in-law calls plants like that a "volunteer".

I have a Sego palm that for some crazy reason has a marijuana plant growing right next to it. Being that there hasn't been marijuana here that I've known of, I'm a bit perplexed. I've heard they can be finicky to grow. We haven't touched it yet because we keep waiting for it to die. No one waters or feeds it...we think my Sego palm, Abner,has a drug problem.. :))

I have some Stinkhorns growing my my gardens occasionally. They look like orange wieners with poop on the top. The flies swarm all over them and eat the poopy looking stuff.