Well, we know that vimanas, and UFOs have been reported in several holy books, including the Bible. Works of art in medieval time often depict these drawn in the skies.

It well might be this is a projectile was to be used in a giant slingshot or trebuchet machine, against these pesky visitors?

: )

A double shell??
 

I know this is a shell, but I'm wondering if this could fit the bill of a double shot for short range?? I've never heard of double shell, but apparently one did exist, so??? It is the right shape. The argument that an ovoid projectile was impractical seems moot judging from this existing projectile.

www.aeragon.com/o/am/index.html

Hi Mark,
Point noted, thanks.
... and link saved intyo my favorits ;)