We've all done it, when a campaign gets a little stale - but just how drastic does this variation get.
Do you use totally random tables and end up with a totally unplayable mess, or do you tweak monsters in minor ways so they look different - or do you simply put your own 'twists' on them.
I personally put twists on existing monsters - I've even had self-replicating Zombies; a variation on the old Fiend Folio Coffer Corpse - but in this case the Zombie 'dies', and as it hits the ground it bubbles and splits open producing two new Zombies to fight (beware of destroying undead with a Turning in my games Lol) - but in todays Blog I shall detail the Fire Troll.
Fire Trolls look like regular AD&D Trolls (or River Trolls in C&C) but with a dark rust coloured hide. They are generally found in hot arid environments, such as deserts or near volcanic activity - they like the heat. When found in the service of another, they are always provided with a method of heating their lair - either by mundane or magical means, its always very hot. The DM should double the effects of fatigue on a PC when fighting in a Fire Trolls lair.
Fire Trolls do not regenerate in the normal way, so they are not as vulnerable to attacks from Fire and Acid. In fact fire causes them to actually heal damage, any damage would be normally caused by a fire based attack (even magical fire) should be counted as healing instead.
If a Fire Troll takes a hit from an edged or piercing weapon it starts to bleed, once a Fire Trolls blood hits the air it becomes flamable - and you should keep a track of how much damage the troll has taken in this way. Each round after it first takes damage, roll a D20 - if it is equal or less than the damage the Fire Troll has taken it explodes doing 8D6 Damage to those within 10 feet of it (save to half damage) - obviously the Fire Troll is now dead and poses no further threat to the Party.
Fire Troll XP - 900 + 12 per Hit Point