[allywilson]

Why?

[kemayo]

It's a slightly-tasteless joke resting on two facts:

1. The [King's / Queen's] Head is a common pub name in the UK.

2. Several queens have been executed by beheading at the Tower of London.

[azalemeth]

3. The word "head" in a nautical context also refers to the ship's toilet.

[Y-bar]

4. Beer head is also another name for the foam

[zeristor]

Divorced.

Beheaded.

Died.

Divorced.

Beheaded.

Survived.

[irrational]

What does that mean?

[JustARandomGuy]

It is what happened to each of the wives of King Henry the 8th. It's a famous rhyme intended to make it easy to remember the order of what happened to them: https://en.wikipedia.org/wiki/Wives_of_Henry_VIII