For the sake of watching all Star Trek series in order of release date, I found myself watching the pilot episode of Star Trek: The Animated Series on Netflix. There are quite a few subtle mistakes. For instance, where the weird orange alien guy is sitting, you can see a genaric red shirt sitting there in the background during a short snippit of dialogue! Also in one snippit, Kirk's pants turn the same color as his shirt! Random and funny.
Also look up Netflix subtitle mistakes. Also found while watching Star Trek (the Next Generation this time): during a tense docking sequence in the pilot episode, the subtitle erronously declares, "All stations, prepare for a happy birthday" instead of prepare for docking, or whatever it was specifically.
Funny, strange, and random.
But if you meant along the lines of creepy, check out Pokemon Black Glitch/Hack. Neat story, kinda creepy. What's worse is a Pokemon Red hack that I've lost the story of. Pretty sure it's not true. Will post if I find it again. HOLY CRAP that scared me! As did "Chuckie's Mom (episode)" on Creepy Pasta. Do not read that.