WARNING: Nerd tales. If you don't know D&D 3.0 or 3.5 this won't make sense. It'd be like me reading about engines in a car magazine; 200CC engine equals a WTF? from me. So I am sure the following is of minimal interest to non pen and paper gamers.
I ran a one session Eberron session that featured a Necromancer as the boss (ie main villain, with a bunch of supporting henchmen in the form of monstrous skeletons). The necromancer was invisible (greater) for the entire fight which, in D&D3.5, makes for a much more challenging encounter.
I have a bunch of house rules that I use in the campaign; for example action points "recharge" to full at the start of each session (action points add 1d6 to a roll, 2d6 if level 8+, and a character has a finite amount that only recharges when they go up a level). Another is if a target takes half their hit points in a single hit then they have to make a fort save to avoid stun.
The necromancer got whacked with a shout spell, failed his safe and was deafened. He almost took half his hit points in that one hit. Ha, I noted gleefully, he nearly had to make a stun check.
At that point C pointed out the Necromancer's spectral hand, a glowing blue hand that allows him to deliver touch attacks at range, was in the blast zone. Now in retrospect I misread the rules and thought he took damage when the hand died - in fact he took that damage when he created it. But since I forgot to take that damage off when created it was only fair I stacked it on the Shout damage when the hand was blown away. This tipped him over the halfway mark and he failed his save and this meant he was stunned for a round.
Damn it. A wizard stunned for a round is in a bad position indeed. They stand there and gibber. And allow horrid players to go snicker snack.
Then, at the end of the fight, another house rule kicked in. Normally in 3.5 once you're under 0 hit points (how much damage you can take) you fall over unconscious. My house rule is a DC 15 Fort save lets you keep on trucking instead but you're at -4 to rolls and concentration checks needed for spells. Also, instead of auto dying at -10 you die when your death number is passed; which is negative number of the average of Strength and Constitution values (or -10, whichever is better)
The necromancer was on -11, still up, but on the cusp of death. He blew his teleport concentration check by 1 and started to flee by foot. Next round he'd was planning on turning to gas and fucking off. As an invisible creature he had a miss chance of 50%, meaning if hit he could negate the damage through a roll of 50 or less on percentile dice - which he managed to pull off several times in a row.
P had a solution to this invisible often missed nearly dead mage issue they faced. I have to admit it was a very neat idea.
P's character, a psionic warforged, had a power that allowed him to grow. Grow big. From 6 feet tall to 18 feet tall. By pumping extra power into it, instead of taking a standard action (you get one of these in a combat round), it was instant.
Falling prone is a free action.
So P's character became huge sized, 18 feet tall, then simply fell over ... onto the square where the invisible mage was. It wasn't an attack on the mage but the square he was in, so a miss chance wasn't granted, and the mage had to make a reflex save to avoid it. Even if he made the save, it was to reduce the damage by half. I ruled a 2000 pound warforged delivered a 3d6 damage spread to each square it landed on. Only 5 damage was dealt.
Only 1 was needed.
The most annoying thing out of it was, that while the mage went squish, all his stuff survived because it was hardy enough to resist the suddenly massive sized head dropping on top of it.
Damn you C and P! Damn you to hell!