Syxsehnz Rod
Sold by Marin Bladewing. If you haven't noticed already, the word 'Syxsehnz' sounds an awful lot like Sixth Sense.
The 
Syxsehnz Rod is a Legion toy sold by a vendor in Azsuna that, when used, transforms nearby Night Elf NPCs into ghostly apparitions — a nod to the phrase 'I see dead people' from the 1999 film The Sixth Sense.
Guide awaiting review
Locate Marin Bladewing
Travel to Azsuna and find Marin Bladewing at 48.2, 73.8 to purchase the Syxsehnz Rod. Note that this toy is reputation-gated, so you will need to reach the required standing before the vendor will offer it.
Purchase the Syxsehnz Rod
Buy the Syxsehnz Rod from Marin Bladewing. Once obtained, using it near Night Elf NPCs in Azsuna or Val'sharah will transform them into ghostly versions of themselves. The toy also works on other NPCs beyond Azsuna and Val'sharah — for example, using it atop the Tomb of the Old Kings in Stormheim converts Restless Warlords into female Vrykul-style NPCs, though they remain hostile and cannot be interacted with.
