Genuine pig

Considering myself as an English literate, I cannot except the fact that I cannot recalled how to spell 'guinea pig'. I spent about half an hour that day trying to recall how to spell and at last, I gave up and as The Bully.

Me: How to you spell 'genie pig'?

The Bully : Genuine pig...

-_-"" I thought I am worse, he is just proved that there is somebody worst. Guinea pig is a genuine pig? Man, he just gave guinea pig a new definition. Poor guinea pig...just which part of you looks like pig???