Does anyone know what the name of this flower is?

This flower came up in my Grandma's back yard in about 4 days. It has no leaves, and is about one foot tall. I have been to local nurseries and flower stores, but no one has ever seen a flower like this before.

 

This looks like Lycoris radiata -- called red spider lily or hurricane lily. It's a beauty.

 

Thank you so much hippofan!!! That's it!