Fallen

I believe this is from a Quercus macrocarpa (bur oak) tree. The acorns are distinguished by very deep fringed cups and are the largest of all native oaks. The common name (sometimes spelled Burr) describes the cup of the acorn, which slightly resembles the spiny bur of a chestnut.

It only took 3 Germans, one American and one Scottish person to figure this out at soccer tonight haha!!