"Kanpan" is a word referencing the infamous event in World of Warcraft that set off the huge in-game revolution; this occured when a player named "Kanpan" stole everything of value from a bunch of players. This word is now linked to double-crossing, loot-whoring, and being a backstabber, all rolled into one. The connotative reference is "shit"
You just stepped in some kanpan. You kanpaned us.
Kanpan is the Japanese word for hardtack, or hard and dry biscuits eaten as a snack or (originally) as military rations.
Sailors in the War of 1812 had to soak their hardtack in ocean water just to make it soft enough to eat. Kanpan is still sometimes used as a military ration in Japan, though most other countries don't. It's also a popular snack in Japan, as it is in Alaska, strangely (the former likely because of issues with postwar rationing and the latter because of extreme remoteness).