I have two vivid memories of being scared to the point of trauma by something seen on T.V. as a child. I am 42 and believe I was probably about 3 when I witnessed these, so we're talking around 1970-71.
The first image is an animated sequence which featured a phantom prospector in a ghostly covered wagon. The wagon was attached to skeletal horses, and I believe the prospector may have been a skeleton as well. The animation was pretty stylized and cartoonish, but what REALLY creeped me out was the voice of the prospector and horses, which had a haunting echoing quality.
The second image I think may have been from a Japanese horror film. A group of soldiers are walking single file through a jungle setting. The soldiers pass under a tree and as the last one passes beneath it, a snake, vine, or tentacle comes down and wraps around his throat, strangling him.
I've carried these images burned into my mind for almost 40 years, but have never been able to figure out what they're from.
The first bit sounds vaguely like the ending to Darby O'Gill and the Little People (1959), which didn't have prospectors, but featured skeletal Grim Reapers and a Death Coach with driver taking souls to the Hereafter?
The jungle one sounds like Navy Vs the Night Monsters (1966), or more likely Mothra (1961) but I've not seen that one in… decades? Shut up, no, it can't be decades! I'm only, uh…
Someone else say something now…
Thanks Derek! I checked out the "MOTHRA" teaser and trailer on youtube, and I'm pretty sure the scene at 1:42 IS the scene I remember. It's amazing how a few seconds of film can make such a strong and lasting impression on a young mind, that's why I LOVE this site.
  "Darby O'Gill" was a good guess, but the sequence I remember was very "cartoonish".