Parody is a form of comedy which takes something that we recognise, usually something in popular culture such as a song or an advert, and changes it.
We recognise the original, and we see what has been changed, usually making fun of the original in some way or another.
Making fun of something by copying it is also the basis of Impressions comedy. We recognise the person that is being emulated, and we laugh due to the absurdness of it, often because the impressionist will enhance or emphasise a trait that the person they are imitating has. They might also mimic their voice, but say something that the real person might not say, but that other people think they mean.
Humour is derived from the recognition of the original and abstracting it.