1. Bad Brew:

This could be a poorly constructed potion, a batch of food made with ingredients that just happen to be bad or merely past their expiration date, or an innocent substitution that has dire consequences (like a can of old dog food used to make a casserole – botulism alert!) It could also be an invention that the character is experimenting with that blows up in his/her face despite any number of tests or re-checking. Could be an error in the math, a misplaced part, you name it. People make mistakes, and as we’ve seen over and over again with accidents like the sinking of the Titanic or the detonation of the Challenger, sometimes those accidents can have deadly consequences.

2. A Really bad trip:

Somehow, a character begins to hallucinate. (Maybe the food was drugged, maybe he/she took something willingly, or perhaps it’s a spell or a side-effect from some covert sci-fi weapon.) The hallucinations are very vivid and very real, and the character should be subtly encouraged to follow them. (Maybe a talking cat says he’ll lead the character to a pot of gold, or a gorgeous butterfly flutters away, always just out of reach, etc.) End it with the character suddenly tripping and falling down a deep well, or diving off a wall onto a spear, or maybe just waking up in the feeding pit of some horrible, horrible beast so you can savor the look on the player’s face when his/her character gets munched.

3. A Bizarre Disease:

Somewhere along the way, the offending character picks up an infection (There are a ton of possible vectors to choose from– spider bite, blood spray from felled foes/innocents, bad hookers, polluted food/water, unsterile transfusions, exposure to exotic radiation, unfamiliar bacteria, etc.) and it goes unnoticed and untreated (or is untreatable/pretends remission) until it gets totally out of hand. There are a lot of fun things you can do with this– think flesh-eating viruses, wasting diseases, AIDS, cholera, the plague, or any of the weirder biological threats you’ve seen in shows like Star Trek or Doctor Who. Heck, maybe it’s a nanogenic pathogen, like Grey Death (Deus Ex) or the nanoprobes used by the Borg. There are a ton of ways to play with this idea.

4. The Stranger:

This one’s great for teaching players to exercise some discretion, and get them to do things that are a little more sane or reasonable than murdering or harassing (or doing worse to) everything they see. Make the encounter happen somewhere isolated, where the character will be more inclined to act on his or her baser impulses. A man walks past the party, simply wishing to be left alone, but if any of the characters do anything offensive to him, ZAP! They’ve been hit by a bolt of lightning, or turned into a baby hippopotamus, or been given an extra set of genitalia somewhere obvious and hard to cover. Of course, the stranger could just zork the offending character for somewhere in the neighborhood of 5d20 points of damage right off the bat and then move along, leaving the other characters shocked and confused next to the pile of ashes that had once been their compatriot.

5. The Pyrrhus Way:

While the roof-tile thrown by an old-lady didn’t kill the once-famous conqueror Pyrrhus exactly, its impact was enough to stun him and give a local soldier the chance to shank him. This is great for characters who run into towns all gungho– let them take on and take down the whole town, let them have their way for a little while, and then throw a miffed old lady in their path who’s a crackshot with something humiliatingly common, like a cobblestone, a roof tile, or a plate. Watch as the bigshot warrior goes down, knocked out cold (or killed outright) by granny and her flying frying pan. There are a lot of fun things you can do with this one too.

6. The Old Standby:

You’ve done it or seen it done before. A character gets out of hand, and BAM! The “hand of God” tosses a flaming chunk of meteor their way, fifty tons of rock collapse above the character and crush them to death, or they become another victim to Bluebolt, etc. It’s the freak accident. It’s the airplane that loses control and crashes into your sailboat, the sudden heart attack, the blown seal on your starship or submarine that suddenly and violently depressurizes the cabin, etc. When all else fails or you just don’t feel like being too creative about disposing of that problem character, use the old standby and get rid of that problem in a way that’s quick, easy, and refreshingly decisive.