Many people will be cooking a goose for Christmas dinner tomorrow, or perhaps roasting potatoes in goose fat. In idiomatic usage to cook someone's goose means to bring about their downfall.
The origins of this phrase are unknown. There are lots of references on the internet to a link with Jan Hus, an early 15th-century religious reformer from Prague, who was burned at the stake. Supposedly, the name Hus meant 'goose' and Hus was alleged to have said before his death that the goose would now be cooked. This story is highly unlikely. Jan Hus was martyred in 1415, yet the phrase 'cook someone's goose' is unknown in English before the mid-19th century.
In the 19th century if there was a 'goose in the house' it meant that the theatre audience was booing and hissing the actors. Goose had been used for centuries before this to mean a simpleton, and phrases such as 'giddy as a goose' referred to the goose as a silly creature.
I won't be cooking a goose tomorrow. I'll be cooking the more traditional turkey (also a word with negative connotations - a turkey is a flop or a third-rate production). I'll be taking a couple of days' break from blogging.
Merry Christmas to all.