For some reason, every time I kill a spider I become more evil.
So far I haven't noticed the same effect from other wildlife.

I have installed the latest unofficial patch recently, could this be the problem?
I don't remember losing alignment points from spiders before.

Also, if it's of any use to anyone. I'm currently playing an extremely ugly dwarf technologist.

If anyone has a solution to this problem, I would be extremely grateful.
I'd rather not skip every random encounter with spiders anymore.

When installing the Unofficial Patch did you start a new game? You need to for the patch effects to take place.

Perhaps the patch broke the alignment of all wildlife (to make it "good" instead of neutral like it is supposed to be - except for pigs, pigs are always "good" I think). I don't know why this would have happened, but it might have if you didn't start a new game.

I did start a new game, so that shouldn't be the source of the problem.

I also tried if initiating combat has something to do with it.
And it didn't.

And still, so far it seems like it's just spiders. Not the rest of the wildlife.

No, I don't have any hexed items on any of my party members.

Going to start a new character and see if that one has the same problem.
Posting back results when I wake up later.

Weird.
I mean, I can sympathise, 'cause spiders are cute and nice critters what eat flies, but this seems a bit harsh.

But hey, if you want to experience the evil side of things, you've got an easy means!

There's no obvious reason for why the unofficial patch would be causing this for you and not anyone else.

Is it only one specific creature type? i.e. do you lose alignment specifically for killing 'lesser spiders', or also greater spiders, dread spiders, etc? I'll assume it's not localised to spiders in one particular area.

Try saving the game, then invest a character point into divination for the sense alignment spell. Activate it and mouse over the spiders. What does the game tell you?

More specific details would also be helpful, like what your character's precise background is, what items he has equipped, what blessings/curses he has (you can get a list of these in the logbook), etc. Also whether your game is modified in any way other than the patches, but I'll assume it's not.

Not just for me apparently, there are other threads around the interwebs where random wildlife seem to cause negative alignment, but for some reason my problem vanished after trying out the game with a second character.

I've got no idea why the spiders (Lesser, Fire, Greater at least) caused the alignment loss, and why the problem suddenly vanished...

I had no hexed items, no curses, just the Arbalah blessing, no injuries. Background is beaten with an ugly stick, equip at that point was just a scimitar, small robes, and chain gloves.

No other mods are installed.

Though, I'm happy I can finally play with my ugly little dwarf :)

Wait, you mean you started a new character, then went back to your old character, and he wasn't losing alignment for killing spiders anymore?

What the hell.