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60's/ 70's /80's Sci fi episode or maybe movie where the characters travel to another planet/ dimension where they (3, male) start drowning in sand till only the hand is left and then nothing. That...

Yesss! That's it! Thank you! :D

So this should be fairly easy to answer.

Movie from the 80s or 90s, where two white american or canadian kids (a boy and a girl, maybe early teens), go on vacation or something, and go to this...