On Fallout 1 when i first met a Super mutant i felt that i was going to die...and i did.in the second game the Glowing One really made me think twice before calling Ghouls dumb,In Fallout 3 i first saw a centaur right in front of me and i remember that moment 'till now.in New Vegas i think the enemie who is the most feared is the Cazador damn creature fast and that poison how many times i suffered to my death with that poison

Fallout 1: Floaters, damn things knock me down and poisons me way too often.
Fallout 2: Wannamingos, I constantly think I can kill them once I get some good gear and then they tear me a new one.
Fallout Tactics: The bugs.... I remember one encounter I got, it was dark all over the map and suddenly an army of bugs came at me. No Beastlords, just bugs bugs and oh so many [censored] bugs! D:
Fallout 3: Reavers, those [censored]ers are scary when you first meet them.
Fallout New Vegas: Golden Gecko's. If there's anything that scare the [censored] out of me it's the Golden Gecko's huge damage. In Fallout 2 they were like the 4th enemy you encountered and they were only dangerous for lvl 4 or below players. But the ones in New Vegas, they dangerous.

F1: I respect the Lieutenant, I used to respect supermutants until I could two hit kill them.

F2: The Enclave.

F3: Deathclaws.

NV: Cazadores.

Fallout: Deathclaws

Fallout 2: Wanamingos

Fallout Tactics: Hover Robots

Fallout 3: Feral Glowing Ghouls

Fallout New Vegas: Cazadores

Fallout: Super mutants equiped with rocket launcher(now thats a worthy oponent!)
Fallout 2: wanamingos(I would love if they returned in fallout 4)
Falout 3: Super Mutant Overloards
Fallout New Vegas: Cazadores(venom amd speed) o rtunnelers(if you count dlcs)

What!? Fear!? Respect!? My Enemies!? BAHHHHH!!

Fallout1: Anything that isn't a rat.
Fallout2 & Tactics: N/A but probablly the same as above.
Fallout3: Reaver, I fought them in NV before getting the F3 DLC and woooo Im glad the were nerfed.
Fallout New Vegas: I respect House, slight fear of Bighorners, try punching a herd without getting knocked down and [censored], and Manti - These bastards pack a punch.

When they introduced new breeds of Deathclaw in NV, that truly excited me and made the game that much more interesting. When I came across my first Mother Deathclaw, I was shocked at seeing such a massive creature. I was more shocked when I saw it's size difference next to regular breeds of Deathclaw; and even more shocked when it absorbed my bullets like a sponge absorbs water and killed me in a single hit.

Oh my goodness, Reavers in Fallout 3 were definitely one of the most difficult beasts that could be encountered in that game, they packed quite a punch for sure.

The only that those gets guys got me worried about was how many bullets i had cuz with the dart gun, anything that melles is pretty easy

See... I didn't have the Dart Gun because I wanted a challenge...Ahh not the face!!!

A dart gun can't stop a reaver cause they will just throw piles of themselves at you. I was level 30 when I saw then first in the train tunnel, and there were 4 or 5 of them... not fun.

Fallout 1: Super Mutants
Fallout 2: These two guys in Klamath that [censored] you up if you try to help Torr
Fallout 3: [censored] OVERLORDS!!!!!
Fallout New Vegas: Cazadores.....

Overlords were a challenge, especially in Vault 87, never have I died so much in such a short time.
The ones on MZ are rather funny. Must stop saying I'm going to redo Fallout 3 and actually do it.

Cazadores they made me delete my Character and start over i made a Topic about it those Flying bastards are so scary and annoying with their poison .

Fallout 1: Floaters - feared
Fallout 2: Wanamingos - feared
Fallout Tactics: The Behemoth - feared/respected
Fallout 3: Reavers - feared
Fallout: New Vegas - Deathclaws - feared

FO1: Supermutants, Deathclaws
FO2: Supermutants, Enclave, Wanamingos
FO3: Yao Guai, Reavers, the Deathclaws in this game were a joke and not worthy of my fear or admiration
FONV: Cazadores, Deathclaws (came back to their frightening former selves!), LEGENDARY BLOATFLY!

REAVERS first time comin across them was in point lookout I was Pinned for three fallout Hours advise dont fight them wen your lvl 10 New deathclaws.

Centaurs. They are one of the easiest things to fight, but they scare the living hell out of me. In real life I would die just looking at them

Fallout 1 - After playing more and clicking the wrong thing, and being punched for not gossiping I have come to fear Lieutenant "Lou Tenant"

I have a system for Fear/Respect.
Respect anything that survives the first volley, Fear anything that survives the second volley.

One word and one word only: Melchior!!

_{FO1: Nightkin, pretty tough
FO2: Geckos, nearly impossible to hit at earlier levels, gosh i hated them
FO3: Radroaches, they are so....disgusting, and these sounds they make, urrghhh. Whereever they appeared they had to die first, even in a room full of Mutants
FNV: Vipers/Jackals with Grenade Rifles, packs of OWB Nightstalkers, Ghost People with Gas Bombs}

deathclaws... all fallouts

F1: Deathclaw
F2: Deathclaw
F3: Guess what! Not a deathclaw, dartgun stopped the fear. Would have to be those reavers. Just makes my skin itch thinking of them..
FN.V.: Golden gecko. You think at first, oh another gecko. Wrong. Still afraid even after mini-nuking hordes of them with tiny tots.

The most feared enemy? The toaster. Why? You meet a psychopath that is unable to move around & knows it. Gives them a body, well lets just say it will not be a very good day.

The cazadores are a pain (when 3 or more).

Just faced a Reaver (Fallout 3) for the 1st time. I was Level 15 & was just roamin' the sewers tryin' to find new locations. The Ghouls I was encountering got sliced to bits with my Vampire's Edge. My melee ability was only around 40, but still these Ghouls were EZ. Then this Reaver chucked some bio-goo on me & I figured I'd just hack him up. It didn't work. He trashed me. I started over & decided to get serious. I laid 6 mines (65 Explosives skill) & lured him to chase me. He endured all 6 mines & I still had to bust him up with the Terrible Shotgun a few times. Tough Character.

Those Super Giant Super Mutants are Killer too.