Bottle

Wanna hear something spooky?
I have an oversized novelty Coke bottle in my den. It’s been there for years, up on the shelf, gathering dust.
Last year, when I picked it up to dust it, it rattled.
There were a bunch of pennies in the bottle.
The thing is, it’s still had the bottlecap on it.
Sealed tight.
When I got it, it didn’t have any pennies in it.
Okay, last week, I dusted it again, and I swear, it had more pennies in there.
How are the pennies getting in there?
Who’s putting the pennies in there?
And why?