When you use this item, you'll be briefly be struck by a lightning effect.
If you don't have any weapons equipped, you can't unsheathe the sword.
It overrides whatever you have equipped in your main hand slot. So if you have the real deal, you can dual-wield two Thunderfuries! ~_^
While the spell effect does override the appearance of your main hand, it does not where weapon enchants/illusions are concerned. That is why my screenshot has the Windfury illusion near the sword's tip.
Edit: Oops, looks like my reading comprehension failed that day.
As Vengir13 wrote, Inflatable Thunderfury, Blessed Blade of the Windseeker (c'mon, Blizz...) is needed in order to earn Did Someone Say...?. It's looted from Anniversary Gift for 2015.
It applies Inflatable Thunderfury to your character. The buff duration is 1 hour (in game time, not real time) and persists through death. You also do not need a weapon equipped; though if you do, then whatever enchantment particle effect is on your weapon will appear on the fake Thunderfury. Attack animations are one-hand sword animations.
EDIT EDIT: The item was stealth nerfed about half-hour ago. It is now BIND ON PICKUP. I directed a tweet at @WarcraftDevs, and I hope someone answers. This is a problem for players who were transferring the item to alt(s) for storing for later use.
Update: It is now purchasable from vendors in Orgrimmar and Stormwind using Timewarped Badges while the anniversary world event is active.
I was saved from myself due to being in a rush on Monday morning, so I only "lost" two Inflatables. Feel bad for others that didn't "luck out". =(
Edit: Oops, looks like my reading comprehension failed that day.
As Vengir13 wrote, Inflatable Thunderfury, Blessed Blade of the Windseeker (c'mon, Blizz...) is needed in order to earn Did Someone Say...?. It's looted from Anniversary Gift for 2015.
It applies Inflatable Thunderfury to your character. The buff duration is 1 hour (in game time, not real time) and persists through death. You also do not need a weapon equipped; though if you do, then whatever enchantment particle effect is on your weapon will appear on the fake Thunderfury. Attack animations are one-hand sword animations.
EDIT EDIT: The item was stealth nerfed about half-hour ago. It is now BIND ON PICKUP. I directed a tweet at @WarcraftDevs, and I hope someone answers. This is a problem for players who were transferring the item to alt(s) for storing for later use.
Update: It is now purchasable from vendors in Orgrimmar and Stormwind using Timewarped Badges while the anniversary world event is active.