Jeff Woodie aka Surfer Dude is one of Dave Miller's friends. He is a surfer dude who loves hanging out at the beach.
Unlike the other kids, Jeff has no particular ability or skills other than fixing the phone with the Tools, which is something Bernard can also do. He may be chosen simply to facilitate Dave and the other kid.
In the C64 version he does not make any noise when he walks, as he is not wearing any shoes. In the PC version of the game, the green tentacle follows him, but still doesn't let him pass without giving it food.
In the original draft of the game, he was supposed to get another ability; being electrocuted would have given him the psychic power of finding out the secret code to open Dr. Fred's lab door. This is hinted inside the "cork board" in the manual, where something similar happens to him.