Samuel (Fallout 3)

Samuel is a feral glowing ghoul, found behind Takoma Industrial, after reading the observation files on the monitor in Isabella Proud's camp. If the Lone Wanderer is wearing the ghoul mask when reading Isabella Proud's terminal, he may glitch and get stuck into the ruins nearby.

I found a glitch by Samuel where you can walk off map for miles on XBox 360. Good weapon testing ground.

I can verify this. At the entrance to the research area where Samuel first appears, turn right, and make your way up the debris. Save before doing this, as I got stuck the first time I tried it. As you approach what appears to be the edge of the pile of debris, you will see an endless expanse of what looks like desert. I tried to navigate to undiscovered locations in the D.C. area, as your cursor still appears on the map, but unfortunately this is not possible. A few buildings have no clipping and you can wander around and explore, but that's about it. Have not tried walking far enough to glitch the game/drop you through the ground.