Halloween and Tonics
Even if they do I would not worry about them, Anet has a history of making holiday items drop like candy (literally most of the times its sweets) from virtually every mob in the game world.
So don’t stock up on tonics, pumpkins, etc don’t drive the price up and don’t end up with stuff that most likely will be worth a lot less during the holiday event.
Cancer is also a Zodiac sign.