Can anyone tell me a word in the English dictionary which has a silent 'z'?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Find the combined weight of the Cat, Dog and Rabbit in the given picture.

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

The below mentioned letters have been placed in a order using a logic.

DEAD, BALL, FEAR, SHOP

Can you find the logic?

Find the next number in the series.
1 10 24 43 67 ?