Maybe about six months ago, Lily was looking through my collection of Munchkin cards, because the art is a combination of creepy and cute that really appeals to her. She would occasionally ask questions if she didn't understand what was going on with a card.
She asked what an Elder Sign was. She understood that there was a joke here, but she didn't quite get what it was. I explained an Elder Sign as a kind of a symbol that keeps certain monsters away. In the absence of such a rune, the guy was just using a sign with "Elder" written on it to smack some monsters.
She thought that this was just about the funniest thing she had ever seen. She wants to share this joke with everyone, because she's certain that they'll find it just as funny as she does.
She was talking to my stepmother, and began the conversation with "You know what an Elder Sign is, right?", because she just assumed that adults all sit around discussing this kind of thing when kids aren't around.
I recounted this all on Facebook, and my friend/Cthulhu GM Eric offered "Do you want to summon shoggoths" (sung to the tune of "Do you want to build a snowman?" from Frozen) in the comments. He later expanded it to a post in his own blog, and I'm linking to it, because, like Cthulhu Munchkin and Eric himself, it's the perfect combination of creepy and cute.