Maybe coat the inside with PVC or PVC veneer?
Now there’s a thought, mini slush moulding . . .
I’m pretty sure @chris1 was referencing this anti-drug PSA campaign from the '80s:
My mother found folks who had a lot of out of date eggs and my father made up an arrangement that used flowing water from a hose to create enough vacuum to such out the (usually quite rotten) eggs and they then ran water in them to clean them out and using a big syringe injected gesso that was drained and then a bit of tissue and more gesso on the outside ( sometimes with a bit of string if it was going to be hung like on a tree) and that done the eggs were ready to have whatever decoration done to them.
They would glue on whatever bric-a-brac and would add a rub on color that highlighted the height differences or just paint stuff like cactus, roadrunners, or quail on them ( in Arizona you can sell anything with cactus, roadrunners, or quail on them) and they had a few places that would sell all that they could make.
With a Glowforge, cutting out shapes to glue on might work better than just cutting the eggs.
And if you know anyone raising emu so much the better.
Or maybe eggs on drugs!?
I take full responsibility for this derailment, but I think @chris1 can take a smidgen of the blame for mentioning the word ‘eggs’ in #11.
@rbtdanforth Thanks for that recollection. My late wife, as a child, hand painted decorations on the eggs shells of the Easter breakfast eggs served to the family.
This is my exit line !
The OP was a dead horse after the first three responses. That made the d-egg- version both a welcome relief and far more interesting.