Modeling with Formula Bottles

The one thing you get with an infant, besides constant feedings, diaper changes, and resetting pacifers, is waste. No, not the diaper kind, the packaging kind. Piles of boxes and bottles with little use beyond recycling.

My daughter uses formula sparingly, but we've still accumulated a pantryful of two ounce pre-mixed formula bottles. They're extremely convenient, but can produce a pile trash.

The lone jungle fighter versus the Chaos babies....

The question of the day is: What can I do with one of these?

The bottles are 4 1/2" high, 1 1/2" across with the center being more oval.

I've already got suggestions using them as pillars, and I'm trying to think of how to use them as electrical transformers, tesla machines, or other wacky sci-fi goodness. Whether it's using one item, or a pile of them, there's got to be some use for them in at least a Victorian Sci-Fi, or Gnome Wars game, but any other suggestions are appreciated.

And yes, I'm pondering using the cheese cracker box in the background as a building, but I've got a lot of cheesey goodness ahead of me to accomplish that.