I Would Have Been Your Daddy

From Halopedia, the Halo Wiki

I Would Have Been Your Daddy, often abbreviated to IWHBYD, is a recurring phrase that was originally spoken by Avery J. Johnson in Halo: Combat Evolved. The IWHBYD phrase is also the name of the first part of the Halo: Combat Evolved level Assault on The Control Room. The phrase may also refer to:

• The IWHBYD Skull in Halo 2
• The IWHBYD Skull in Halo 3
• The IWHBYD skull makes characters say rare, weird, or uncommon dialog