The Sphenoid bone is part of the human neurocranium, a collection of bones in the skull that forms a protective case for the brain. It is located behind the eyes.
Perhaps the most striking thing about this bone is how it resembles a pair of bat or butterfly wings, like this:
It kinda matches the shape of the communication mask thing Hawkmoth uses as well:
“We have an akuma inside us all.” -Mod Jae
(Data source: X)