Maybe a KIDNEY.
You already have his testicles.
The Big Bang Theory Season 11, Episode 9
Kidney? Cornea? Piece of his liver?
The Big Bang Theory Season 8, Episode 20
You wanna see
James Cameron's KIDNEY stone?
The Big Bang Theory Season 8, Episode 7
Well, I never told you
about my brother's KIDNEY stone.
The Big Bang Theory Season 7, Episode 11
A good KIDNEY pie is all
about the ingredients.
Game of Thrones Season 4, Episode 7