If you’re planning on taking a severed head on vacation this summer, just make sure it’s “properly packaged, labeled and declared”.
At least if that severed head is that of Jeremy Bentham, an English philosopher who died in 1832.
The TSA runs an AskTSA that lets travelers find out what is and isn’t allowed through security. Some inquiries are stranger than others like the person who was “wondering if it’s OK to bring this mummified head of Jeremy Bentham as a carry-on item. Thanks!”
The head is on display at the University College London Institute of Archaeology, so it probably isn’t going anywhere soon, but if you have your own severed head you’d like to take on a plane make sure to @AskTSA.