wizard hat

n. [also, after Terry Pratchett, pointy hat ] Notional headgear worn by
whoever is the wizard in a particular context. The implication is that it's
a transferable role. Talk to Alice, she's wearing the TCP/IP wizard hat
while Bob is on vacation. This metaphor is sufficiently live that one may
actually see hackers miming the act of putting on, taking off, or
transferring a phantom hat. See also pointy hat , compare patch pumpkin.