Either dangerous to yourself or others. Personally i have yet to master my favorite spell lightning. Evertime i cast it i seem to fry someone in my party with that damn richochet.

Incendiary Cloud can be seriously hazardous to your or your party's health if improperly casted.

I like magic missile and Fire ball, I especially like to enter a room where I know lots of bad guys lurk waiting to eat my lunch, with Stinking cloud and then fire ball. Sometimes i even toss in another fire ball for good measure. Took care of those two bad assed trolls in the basement of Nalia's keep with that one and didn't even have to raise a sword.

My most dangerours spell to others, mordenkainen Sword. Most dangerours to my party, Sun Fire.

WITHOUT A DOUBT! "BLADE BARRIER" (Cleric spell.) it slices and dices Big time!! and if your party is to close to whoever cast it, well lets just say someone will be picking up the pieces..

Gotta love that death spell--reducing an entire room to little puffs of smoke!

...i have recently fallen in love with the various summon spells...does that count as dangerous? i like the invisible stalker and the nishuruu a lot...they are my buddies, you might say...outside the mindflayers lair during the rescue mission those guys took the brunt of the pain! that should count for something!!

I personally like to cast web and entangle, then throw in a couple of fireballs, then cast freedom of motion (I think that is what the spell is call that allows you to walk through webs and the like) and hack and slay. I also you Magic Missle a lot. real bitch when you put 'em in a sequencer for both your mages and cast them at the same time. 20 magic missle hitting a mage before their sequencer goes off is great. Not so good if it doesn't hit first and they all bounce back. (oops)

BK

i gotta say, the ol' cloudkill was one that almost took my whole party out in the graveyard chap3, i cast it and got rid of all the baddies, and then im sauntering around the room, scav..um, er, looking over the suddenly available wares at great discounts, and my people are going "uhn" "ahh", and like the dialogue box is going yoshimo 9 points damage, and like i'm curing people and they're like still taking damage and going, like, "ooh", "ahh", and like all of a sudden i realize that the little dog-diarrhea looking puffs are like the effects of the cloudkill wand that i just used that i had been carting, like, since the first level. oops! only had one char in double digit hp, no healing spells or potions, if i had been waylaid back to the inn, well, like, insert porky pig's signature line here. _____

Abi Dalzim Horrit wilting
without a doubt
i mean if you can do 60 to 100 damage to every opponent in the area
what else do you need?
killed both firkraag and the black dragon in no time (litterly no time becoz of the timestop) with ADHW
And ofcourse timestop but that one isn't directly dangerous

most dangerous for my own party?
Unholy Smite