kick the bucket

Etymology
"The bucket" was the wooden frame that slaughtered (geschlachtet) animals were hung from. Some animals managed to kick the bucket before dying, therefore this idiom.

Death is never a pleasant subject, and maybe black humour is some kind of emotional compensation. Here's a selection from the hundreds of (humorous) to-die idioms floating around the English language:

Married to OJ (Simpson)
On the unable to breathe list
Tailgating with Jesus
Put on the wooden overcoat
Electrocardiographically challenged
Gone to meet the maker
Gone to the great big blue screen in the sky
Ded: d. e. d.
In a better place
Worm food
Not with us
Pass on
No more taxes
Got Ghosted
Departed for the Celestial Kingdom
Emptying the Great Hole Punch
Lost his franchise
"Daddy done went on vacation." - Forrest Gump
Assume room temperature
Improved the gene pool
Become living impared
Won the Darwin Award
Pushing up the daisies
Moved into upper management