I'm not normally into joke items but I thought of this a couple of days ago when I was rezzing an AFK player and thought it would be amusing.
A Karka Egg Clutch that is dropped at places where people AFK a lot. If someone goes idle for more than a couple of minutes the eggs hatch and karka cling to the AFK player(s) covering them completely in karka hatchlings. Make it persistent like guild banners but block it's use in cities and lounges. On the non-joke side make it so that when players are covered in karka they can't be attacked and killed so others won't have to keep rezzing them. While it could be a consumable item it might be worth making it a gem store item and give it an hour cool down between uses to avoid spamming.