Colored Elephants

How do you kill a blue elephant?
Shoot it with a blue elephant gun.

How do you kill a red elephant?
Strangle it until it turns blue then shoot it with a blue 
elephant gun?

How do you kill a yellow elephant?
Tell it a dirty joke so it turns red, strangle it until 
it turns blue, and then shoot it with a blue elephant gun.

How do you kill a green elephant?
Don't be silly. There is no such thing as a green elephant.