The Old Gods return, but instead of rising from the depths of the ocean clamouring for human sacrifices, they crawl out of the bogs and demand we return their butter.
Samuel Pepys had to bury an entire wheel of good Dutch cheese before fleeing the Great Fire of London after all, so this may have been a similar situation...
They should DNA test it and find the surviving descendants of the cows (or whatever) the original milk came from and get them together with the butter for a photo op and… I think that’s enough.