I can't watch YouTube right now, but maybe the things you're talking about were.... game glitches?
Pokemon games, even X & Y have glitches, but before Ruby & Sapphire, they're really creepy. (>~~<)
Yes there are creepy glitches but that's not all of what I am talking about. Here are some non glitches creepy stuff that I am talking about...
Lavander Town from the first generation. It has acual zombies in it! Zombies!!!
the old Chateau in generation 4 has ghosts in it! Not pokemon ghosts... people ghosts!
Lumino City in pokemon XY in one building you go into the elivator and then a clip shows up and a creepy looking girl appeares behind you and then walkes infront of you and says, "No, your not the one." Then walkes away without a trace.
Don't beleve me? Pull out your pokemon games and find them. I don't know what tha heck the last two mean at all!