Pickled worms have always been something I've found rather unpleasant.
Written like that it sounds patently obvious - I mean, pickled worms. Pickled. Worms. Ew. You'd not expect to find people who say 'Mmm! Pickled worms! Bring it on!'. But I really have come into contact with more pickled worms than you'd expect, and than I'd like - it's a result of having studied Zoology for a bit.
Old-school A level zoology courses (and, for that matter, the bit of degree I did too) were broadly based on comparative anatomy - you know, the reason that natural history museums have all of those skeletons of different animals displayed in their main rooms; so that by looking, you can see just how similar the constructs are. It's a simple demonstration of the power of evolution to produce a smart, adaptable design (although that sentence does rather anthropomorphise 'evolution' as a thing that designs, which it absolutely isn't - it's a random process of winnowing out the chaff through breeding).
Part of studying comparative anatomy involves cutting things up. I used to be a whiz at dissecting out frog nervous systems; imagine trying to preserve a 2mm thick thread of soft cheap hot-dog meat whilst cutting away a surround with the consistency of expensive sausage skins, and you'll get an idea of the manual dexterity you need for doing that. The thing I used to find less enjoyable though, was dissecting worms.
I'm not someone who is scared of spiders. At all. But I do have an irrational dislike of maggots. Not quite a standing fixed screaming, but a definite can't-bring-myself-to-stand-near-them sort of thing. They disgust me, in that visceral, nasty, primal way. It turns out that maggot fear intersects in quite a bit way with annelid fear, too. Not earthworms, no - they're kind of cute, and harmless. Quite happy to pick them up, no problem. Even marine bristleworms are ok; some of them are quite pretty, and what's more, they explode en masse when they have sex, which is somehow almost endearing. They're definitely less cool than earthworms though, and the ones with fat jaws start to hit the squick button, too.
The fear actually intersects with a mild flatworm/fluke/leech disgust - so fat, wriggly and... Juicy, blindly seeking the chemical incline that brings them closer to your nice, tasty blood... Which should give you the clue that the fear really intersects with parasite disgust - so, roundworms, hookworms, tapeworms and so on. Anything, in fact, that gets inside you and uses its nasty little prostoma to... Ugh. Well. Do whatever it is that parasites get up to inside you - squirm disgustingly inside your gut like living spaghetti, mostly, I expect. So its a disgust based on foreignness inside, on having things inside you that shouldn't be there, gestating quietly inside your body, or consuming you from within. Hmn. Freudian. Anyway.
This is where the pickled worms come in. When you're given them to dissect, they come in big jars. They've gone hard and waxy from preservation. They're bone white, and glisten slightly, pointed at each end, sort of the dimensions of a crochet needle. They smell of formaldehyde - sort of a mix between vinegar, rot and treated chipboard. You have to tweezer them up and pin them out. They're kind of springy, and leathery, and ooze fluid as you scalpel them open. And. And. And.
It used to take huge efforts of will for me to handle them. You can imagine. Of course, the fact that it was worm dissection day was never a guarantee that you wouldn't encounter them anyway - cutting into a dogfish gut reveals a tightly coiled wire wool of worms. I haven't eaten Rock from the chippy since.
And there's never a guarantee that you won't encounter the horrible things randomly elsewhere; in catsick (particularly memorable those, they were about 5 inches long and still thrashing...), or insinuating their way out of a piece of Cod you bought from Sainsbury's and kept in the fridge for a day or two too long. Their sheer ubiquity is what gets me too; they're everywhere. Inside. Ugh.
I imagine, by now, that you're feeling as unwell and jumpy as I am. So, sensitised as you are to just what it is that makes me squick about worms, I'll pass you on to this article about a new medical robot designed for investigating the gut.
I haven't been able to bring myself to watch the video.
Excuse me, I'm just off to quietly retch and pass out in the corner.