It's one of the comics being made available in an exclusive edition for Local Comic Shop Day. But it has also sold out of its standard version. Twice.
Grant Morrison and Dan Mora's first issue of Klaus, that details a historic origin of the one and only Santa Claus, has sold out at the distributor level again. A third printing is now being arranged to ship on the 23rd December.
These are the covers from the first two printings of the comic. The third will be unveiled shortly.