There's something in my vase!

It's been there for months. Occasionally, I'll hear something that sounds like someone dropping a kernel of popcorn or 2 inside of it. All by itself... It's creepy. I want to investigate, but I'm not sure I even want to know what it is! I could turn the vase upside down, but what if it's some strange insect or something? Can an insect live THAT long in a vase with no food? Any ideas?