The Transylvanian border guard was a one-time character in the Inspector Gadget episode, Haunted Castle.
Routine[]
He was on night duty at the Transylvanian border, when he suddenly grabbed by Dick, who tied him up and gagged him and took his uniform. Taking the guard's place at the border, Dick sees Inspector Gadget, Penny and Brain approaching the border in the Gadgetmobile.
While Gadget talks to Dick about their directions, the guard attempts to escape from his booth, but he was repeatedly thwarted by Dick, who discreetly pushed him back into the booth.
What became of the guard was unknown. It was likely that he was found by the police and rescued off-camera.