I wasn't a gullible little girl, but I could be a mean big sister.
I had my little sister and her friends convinced for years that we had an uncle who was buried in the unfinished side of the basement (so that I would have a good place to hide for hide and seek).....our heater in that house made a lot of noise at night, so I told her that the thumping was a robot that was trying to climb up the stairs every night to get us.

"Let your soul shine, It's better than sunshine, It's better than moonshine, ****** sure better than rain." -ABB