Anything that suck your blood, and even share with you parasites when doing it! Im talking about you, damn vinchuca and your Chagas disease!! A few years ago in Costa Rica, I was bitten by HUNDREDS of tiny ticks. It was horrible. I spent a long time thinking that I might have even caught some kind of infection. 
Don’t wear blue clothing this seems to attract them
Ticks-Since moving to Florida I seem to get at least one per year. I worry that I will end up with Lyme Disease or allergic to meat…! Don’t care for mosquitos either. I apparently have the blood type they prefer so I get bit a lot. Both are so tiny you don’t even see the attack coming. I don’t really care for spraying chemicals all over my skin to prevent their bites. Not sure which is worse.
Dude if you consider one tick a year to be “a lot,” you don’t know how lucky you are
You’re not kidding. I’ve had years with hundreds.
i have a vivid memory of being a high school senior (17/18 years old) walking outside with a classmate, he found a tick crawling up his arm and nearly had a panic attack. i may have been a smart aleck and asked ‘is this your first time outside?’ - i can’t recall. picking off ticks was a standard summer activity for me as a kid, and i frequently had poison ivy rashes and mosquito bites. i guess i was an itchy kid, i don’t remember 
i try being less nonchalant about the ticks nowadays, mostly keeping my pants tucked into socks and avoiding shorts. annoying!
i know a lot of local naturalists have alpha gal syndrome. i don’t eat meat, so i’m not sure how i’d know if i get it…
I don’t think I claimed it was a lot. Just what I get.
Seed ticks are the worst. I’ve had multiple instances of walking through a “nest” of them, feeling tickling on my leg, and looking down to see literally hundreds crawling on me. In that circumstance a roll of tape is your best friend
I may have misread the part about getting a lot of mosquito bites to be still referring to the ticks
I’m also quite scared of jellyfish. Although I never have gotten stung, it still scares me a bit at the beach (on the ocean).
Where do you live that you find so many?
Alligators-any fresh body of water here in Florida very likely has some. You don’t actually have to go in the water either. They can hide just below the surface of the water.
I have had them blocking my path to get back to my car. I understand they are very fast. Though to date I have not seen one move fast.
Truthfully? Homo sapiens.
Because of my health condition which restricts me mostly to walking, not driving, most of my hikes are through urban parks in a mid-sized city which I’ve moved to from a small town, just a year ago.
It’s taken me a bit to get used to stumbling upon people’s ‘camps’, or almost tripping over sleeping people in the denser parts of even small parks and parkettes.
Most of my interactions with homeless nature ‘campers’ have been neutral or occasionally cordial, but I have also come across many who act quite fearfully defensive or deeply confused.
There are no easy answers to the problems that this new and growing urban reality presents.
I try to avoid areas that contain a lot of clues of temporary parkland habitation (mostly a lot of concentrated trash) and try to respect the gruesome struggles that I can’t possibly fully understand.
But I struggle even more to understand why we can’t do more as a society to help people from having to choose to live this way. The safety nets are broke or breaking. Pretending that it isn’t happening or ignoring what isn’t easily visible isn’t working either.
Scarier still? Political leadership that chooses to ignore the growing problem and/or looks to policing and by-law enforcement as the only solutions.
Grew up in Louisiana, the tick population there is pretty insane. Now live in Virginia, where there are thankfully a lot fewer
I, too, really don’t like ticks thanks to the North American diseases they can carry. I took a trip to prairie in southern Ohio a couple of months ago and had itchy ankles and feet afterwards. Took off my socks and had over ONE HUNDRED seed ticks burrowed into me. Argh. Started a prophylactic course of antibiotics as the chance of getting Lyme Disease was just unappealing.
I don’t like Leeches much either.
fungi. The molds freak me out. They may be harmless but it is a phobia.
Yes ticks too.
Apart from that: snakes (luckily never encountered one but just thinking that one could be in the bush freaks me out), maggots (why are they gross I like all sorts of insects, grab geckos, and even some other pretty crazy things) mites (which are often harmless), then I hate mosquitos, and am very careful while grabbing assassin bugs or horseflies.
I think for me it’s anything potentially venomous/poisonous or otherwise harmful because I don’t know enough to differentiate them from the harmless ones. Like, I know what a garder snake looks like, or a daddy long legs spider (don’t know the proper name), and I know they’re harmless, but I don’t know what this random black spider is and if it’s harmless or not.
I don’t really have a fear of them, other than the initial jump scare, more like heightened caution.
I’m scared of very few organisms, honestly. Though I’m very glad that Loa loa isn’t common in my part of the world. Definitely gives me the heebie jeebies!
(Wikipedia article for context. No graphic images but icky descriptions!)
There are many organisms that I would be afraid of, if I lived where they are found (venomous snakes! poisonous spiders! ravenous alligators!) But in terms of my iNatting activities, like other people here, ticks are high on my list of fearsome foes, because I live in New England, which has a high prevalence of Lyme disease.
Not only am I afraid of ticks, I am annoyed at them, for causing me to be super cautious, and to not casually pop into the woods or fields without first dressing to minimize contact, and then immediately jumping in the shower afterwards.
I would make a lot more observations, without their menace!