BloodRayne: Betrayal Hints for Xbox 360
Also on: PlayStation 3
You can find A Boy and His Blob in BloodRayne: Betrayal! While on the 'Escape' level, having gone across both pits of lava, jump up high on the left-hand wall and climb it.
Once you get to the top, go quickly to the right. Continue right and you will find the red skull. Wall bounce your way over the last wall and you will come upon the Boy and his Blob in a cell!