My first encounter with a Mirelurk Queen scared the heck out of me.

A horde of synths coming from every direction. First time I saw one was in a bunker to the top west of map then the second time in an old people's home somewhere east.

Feral ghouls! I love them but they freak me out. That noise they make & the way they move. If putrefaction had a noise it would be that. Much better then the F3 ghouls.

MIrelurks are very creepy, scuttling towards me they freak me out a bit.

Those blasted cymbal monkeys! My biggest mission in Fallout 4 is to rid the Commonwealth of those infernal things!!

Lol yeah, my first encounter with one of those freaked me. I just expect it now.

I'll go with the ghouls, like those before me. It's just the way they move. Crawl out of gaps, run towards you etc.. Again, swarming you. These guys are freaky, and very dangerous in numbers. I usually cripple their legs first now, to gain a little crowd control. Seems to be working so far.

Bethesda did a really good job on these guys.

Anything that leaps out when I least expect it lol.

Assaultrons are the only ones that make me think "oh no!" The sound of the death ray warming up, the knowledge that you have only a few seconds to take them out, and suddenly remembering that it's been fifteen minutes since the last quicksave provide the greatest sense of dread in the game.

The most annoying ones are bloatflies - too quick to shoot, they dodge out of melee range and keep firing their toxic maggots. Not so bad since I added the electrical discharge to my armour so I am now a walking bug zapper.

Nope Death claws freak me out the most when I am out in the middle of no where with no way to get away. Second I would have to say ghouls just for the jump scare factor although an immediate application with a Super Sledge seems to sort them out. And Synths might creep you guys out do to the "Uncanny Valley" principal. which is exactly what its designed to do.

Yeah, this was not a pleasant sight
http://steamcommunity.com/sharedfiles/filedetails/?id=566364565

Of course the real monster in that picture is the gun, who proceeded to brutally savage that poor lizard

Lol yep exactly especially on Survival, two hits and your toast, maybe one for a glowing but the legionaries can do it in two.

What freaks me out the most are raiders who stand on the floor above me or so and notice me while I'm sneaking, so that they'll start talking and sound as if they stand right next to me or behind me. I always cringe when that happens, it's awful.

But the Deathclaws are WAY too easy to kill now... and not it in power armour either. Even the glowing one I took down in about 20 seconds. Just... too... darn... easy (compared to Fallout 3 that is).

The one that really freaks me out in Fallout 4 has to be Mirelurks. One nearly game me a bloody heart attack when I was sneaking up on some Gunners. Sneek.... sneak... BOOOMF.... Popped up right in my damned face... Scared the bejeezus out of me. AND THAT SKITTERING SOUND.... *shudders*

OMG... What I hate about Assaultrons is... they keep getting the last laugh with me... EVEN WHEN I HAVE KILLED THEM. Yup.... that damned self destruct nuke thing. I kill them... go to loot and KABBBBBBBBBBBBBBBBOOOOOOOOOOOOOOOM! *BLEEP* *BLEEP* *BLEEPITY* *BLEEP*

I hate Mirelurk Queens that acid! Suiciders are a close second. Ferals make my shotgun giggle maniacally! The first Mirelurk King I ran into made quick work of me. Assaultrons are brutal too and yes there is a legendary version. Most recently I ran into Legendary Mr. Gutsy who tore me to shreds at level 42. Maybe I should try wearing power armor sometime? Haven't worn any since I got my first set.

Probably blood bugs and Ghouls. I was ambushed basically by about 9 or 10 ghouls in a city area. I thought there was only like 3 and then a heard of them came roaming around the corner and I couldn't take care of them quick and they literally pummeled me to death. Blood bugs are just hard to hit once you run out of AP, and there have been a few time's where I would become overwhelmed by a few. Hard difficulty here.

Definitely the scariest moments for me were the first time a ghoul crawled through a window in the super duper mart, I just couldn't believe how creepy and resident evil it looked and the encounter in the museum of witchcraft - won't spoil but that is a nice creepy atmospheric place.

Now-a-days though I have to travel to the glowing sea if I want to really feel on edge, just last night I accidently dropped into the church through the roof rather than entering properly and was instantly surrounded by 6-10 ghouls, a glowing one and 2 legendaries! Thankfully I carry a Lucky Automatic Shotgun and have 2 criticals banked in case of this sort of situation.

Assaultrons.

I hear the sound of a deathray charging up, all the while they cloak, melee and dodge to buy time before they melt through any defense I have and rip me.

Blood bugs, especially the legendary ones. Sure they're not that tough most of the time, but there's still something unnerving about them...

Also, Museum of Witchcraft...

Legendary Bloat flys, they are just too fast, fly around, are realy small, have alot of health, and can poison you from super far away. Their are so few pieces of armor that are resistant to poison and its always like +15 poison resist and I'm like "are you kidding me?" They need poison resistant cloths and antidote to resist poison or remove poison damage done to you.

Legendary Assaultron Dominator.

there's a lot of this game i haven't experienced yet

scariest: 1. ghouls 2. molerats

these are the freakiest, but as far as fear of death:

1. mutant suicider 2. molerat suicider

I've searched many places for chameleon deathclaws... cant find em... and Im level 80.

yea, you hear that buzz buzz buzz in your ear, and you're looking around like wtf...then all of a sudden there's a bug the size of a sewer lid svcking your blood xD

This.

Of all the updated enemies in the game, Radscorpions are the ones I see and simply just want to run away screaming the most. I fear them more than Deathclaws, and I can't figure out why. They are just really well done.