I would say buy some big plastic bananas and then buy some of these
And transplant the guts of one into another. And reverse the light so the banana lights up from the inside. Then just lengthen the switch to be at the bottom of the pole.
I like this idea but the item seems a bit small. I need something a bit more realistic in size or oversized. I was hoping there were novelty patio lights or something. The closest I found were solar powered banana lights.
The sights I found these bananas on were only sold in bulk.
I think you missed the part of transplanting into a big plastic banana. Those key chains are no bigger than your finger. Really it's what's inside them that counts.
Buy it and use up whatever is in the container. Once it's all outta juice drill a hole in it carefully and slowly to get the rest out.
Retainers are small. Unless he's showing it to the audience would just get some thing like a night guard.