I remember years ago how I loved the unexpected in Diablo2; when I was still new to the game and any little thing would make me wet myself. As an example, I found the Catacombs scary, especially after opening a door and coming face to face with a vampire, that proceeded to fireball me. That huge 'BOOM' when the fireball exploded and/or my char screaming in death was enough to make my heart skip several beats!
Sadly, not a lot scares me anymore after all these years. But one thing took me by surprise the other day. In Baal's throne room there were Horadrim Ancients (raising the undead) and Death Knights. After killing the Death Knights, I headed for the Horadrim Ancients. Suddenly I see two Death Knights that I killed, still face down on the floor, slide up to my char, before getting back on their feet and chopping away with their swords! It reduced my life orb to about 1/8th and scared me silly!
I later realised that the Horadrim Ancients raised the undead Death Knights back to life, but the game must have a display bug that caused them to slide to my char face down, rather than getting up from where they died and then walking to my char.
So it got me wondering... what do people still find scary in Diablo2? The more horrifying and/or funny the story the better.
Seriously, though, I still get a tight feeling in my chest when I'm going up against an act boss for the first time with a character. Any act (especially act 4), any difficulty. Part of this is due to my new love of hardcore play, but in general I find it thrilling when the character is just strong enough . . . maybe . . . to take on one of the big guys.
If you really want to still get scared, play HC as durf mentions.
I went up against the hell ancients a week or so ago, with my latest guardian candidate, and I thought my heart was going to pop through my chest. It really does get the blood going. They're always scary. And anytime I'm in the Worldstone Keep in hell difficulty, I'm quite nervous. The wrong combination of monsters and auras down there, and it's easy to get your Deeds.
For me, getting hit by strong poison and having my life bulb drain away in an instant - especially as I play HC. Also fighting Diablo, the Ancients and EVERYTHING in Hell mode (so fighting the Hell Ancients = heartbeat through the roof). Hell mode really scares me because I'm not very experienced in playing in it.
Undead Stygian Dolls worry me a lot too. I always let my merc/minions handle them since they just hurt too much when they explode.
With the loss of the FE bug (more of less) in v1.11, not a whole lot scares me PvM wise. Conviction gloams are still troublesome, but most of my characters are designed to take them out quickly enough.
Which brings me to my one thing: Lister. I hate Lister, especially in hell. This is mostly because of my Hammerdin (see the lvl 99 thread). If I ever need to abort a run, it's because of lister, and the fact that he spawned one or two of a couple of really tough mods (Extra fast, might, fanat, or something along those lines). Most of the time, I can kill him with little trouble, but it's those times where he spawns are you're merc is dead in .01 seconds that makes my heart jump.
As for PvP, Kab's latest BvA creation, TUB :lol:, is the scariest PvP character I've run into since v1.09.