Eighteen human heads were found by customs agents at Chicago's O'Hare Airport, but don't fly off the handle just yet—officials believe they're part of a poorly marked medical shipment. It isn't illegal to ship body parts, nor is it even't strange, but it's up to investigators to decide whether or not they're authorized medical specimens.

Speaking with the Chicago Sun-Times, Department of Homeland Security spokesman Brian Bell said "Everybody here is ‘Oh my gosh, you got a box of heads’ and everybody thinks that it’s unheard of." “It is a potentially legitimate medical shipment. We’ve seen it at various ports in the nation," Bell added. 

The Cook County Medical Examiner's Office says that no foul play took place in the collection of the heads, but officials refuse to say where the package came from and where it was headed—no pun intended.

[via Chicagoist]