Remember Dr.Kleiner and Lamarr?
This is another pair of characters with the same kind of bond, only with one more characteristic; the scientist can decide wether to decide if should be "zombified" or not. It can be further explained by the phrase as "being TOO SMART for the Headcrab", which means that the scientist's superior intellect has overpowered the headcrab, rendering the headcrab harmless and cancelling the zombiefication process.
If needed be, the scientist can ask the headcrab to temporarily zombify him to help him gain an advantage on the battlefield; superior strength, etc.
Ps. The Scientist and Headcrab are both yet to be named
try submitting some suggestions
>>>>The HL2 style Mug was inspired from JABUKA96's design ;D
Which is much more awesome than the mug in this drawing[link]