I know this is late but I am going to still do it. For anyone who has not seen Skymin Slash's TF2: Was There a 6th Power-up Canteen Upgrade? The video is about the unused 6th Canteen. Skymin has pointed out that there were many voice lines that say " Sapping Robot" This implies that the 6th Canteen could be used to sap robots. There is also a shot up portion of the MvM update page that seems to have a picture of a Canteen. This will also reinforce the theory that there was a 6th Canteen. Valve has taken this canteen out to not diminish the spy. There can be an away for the Canteen to be in the game without diminishing the Spy. Version 1 You can have this Canteen act like the Spy's Sapper in the way that once activated there will be an area around you all robots will be zapped. The Canteen should have the area of the level 2 upgrade to the range. This will make the Canteen effective enough that it would not be a waste of money. The price should be 75 dollars for it. The Spy will need an upgrade to his Zapper to now be overshadowed by the Canteen. He zapper should get a new upgrade to either drain uber from giant medics at 2 percent every second for 20 seconds. That would cost about 250 dollars. The Zapper could also get a recharge upgrade at 150. If the coat is too cheap then it can be increased by 50 dollars. Version 1.2 Everything would be the same for the first version however inside of the Canteen activation right away, it could spawn a Zapper in your hand then you can throw it like any other throwable. Like Mad Milk and Gass Passser. Version 2 The Canteen can send an EMP blast to disable any Engineer builds in a certain area. This might not be too useful for more experienced players. However, this would work great for newer players on Bigrock and Decoy where there are a butt ton of Engineers. The coats would be 50 dollars.