My party fought a purple worm recently. It devoured the cleric. Then the sorcerer used polymorph on it to turn it into a frog, which caused the cleric to get squeezed out of it like toothpaste in a tube and shot out of it and collided with the cavern ceiling, taking ‘fall’ damage. Then the cleric used divine intervention (successfully)… as a divine avatar they swooped down and crushed the frog between their hands, releasing a tidal wave of venemous worm viscera to wash over everyone causing them to take massive poison damage. Great fun :D
In terms of your plan, drilling a hole in the rod may cause it to lose function. Also a general rule about polymorph is that there needs to be room for the transformation, and a general rule for invalid creature placement is that creatures take a small amount of force damage and are moved to the closest available space. As your DM I’d probably say you couldn’t end polymorph early while it’s in the rod, and if you lost concentration or the duration expired, it would be shunted next to the rod and take 2d10 force damage.
Actually what I’d like to do is have the worm trapped in the rod, make you believe it died, and the next time you used it the worm would appear.
Nature is brutal. It’s UNNATURAL to limit oneself to eating things with less nutrients. Being one with nature means you kill or be killed, and only the fittest survive.
Now the difference of philosophy here is that the structure humans have created is much more unnatural than that. A druid would agree that going out into the woods with a bow and shooting a deer is fine. But going to a restaurant and ordering chicken that was raised in a barn, for the sole purpose of consumption, is wildly unnatural.