This is RPG-ology #99: Flies and Fairies, for February 2026.
Our thanks to Regis Pannier and the team at the Places to Go, People to Be French edition for locating a copy of this and a number of other lost Game Ideas Unlimited articles. This was originally Game Ideas Unlimited: Flies and Fairies, and is reposted here with minor editing [bracketed].
When I was younger, I learned to catch flies. There’s a lot to it, actually; they move very quickly and react instinctively to attacks. But you can catch them.
If you are attempting to catch them with one hand, unless you are lightning quick from training, you need to aim not for the fly but for the place where the fly will be when your hand gets there. A fly on a flat surface has only one place to go when the attack comes: up. Thus if you aim your attack for about one and a half inches above the surface, you will almost always catch the fly there. If the fly is not on a flat surface–say, on the side of a cup or the corner of a wall–the odds are considerably more against you, because it has more directions it can go.
There is an advantage to using two hands to catch a fly (except of course that you almost never catch them alive this way). The fly’s brain is simple, but adapted to avoid predators. It can instantly plot an escape trajectory from an incoming attack. But it cannot so easily plot a trajectory to escape from two incoming attacks. None of the creatures it seeks to avoid have the capacity to strike from two directions at once. If your hands are approaching from opposite sides, the fly is slowed as it vainly attempts to process a flight path that avoids both. If you’re quick, you can catch the fly still on the ground
Ultimately, you don’t get the fly because you’re faster than it is, or more agile. You get the fly because you’re smarter. This is important to remember in your role playing games. If the referee consistently designs opponents who will always lose to you in a straight fight, and then plays them straight, the game is sure to get dull eventually. It is much better to face an opponent whom you have every reason to think is more powerful than you, and to find a way to beat him anyway.
But why are flies so annoying? They buzz around us, and we know that we have enough power in our smallest fingers to crush them–yet they elude us. This enlightens an aspect of game design which many people miss.
Someone put me on the official discussion list for their game in development, and I didn’t protest because I knew the guy. The list included several stabs at play and discussion of upgrades and improvements to the rules. On one occasion, the official game designer announced an adjustment to the system that would base the injury capacity of characters and creatures in part on their mass; thus a giant would be able to survive more blows than a man, all other factors being equal. Immediately one of the players objected. His character was a fairy, a very tiny winged humanoid modeled on Tinkerbell, and he had been assured at character creation that this would not impact his survivability. Clearly under the new rules he was significantly at risk; he could not survive the damage which a character could expect in such a game.
There was much discussion over the next few days about how to remedy this. The game author kept trying to tweak the other factors in the damage level of the fairy to get it high enough that it was not a problem, but this was starting to seem a bit ridiculous, particularly as it was the sort of game in which each number affected several things in different ways. Yet the answer seemed so obvious to me; I had faced it elsewhere.
In designing Multiverser, I had used it to run scenarios for friends, to test the mechanics. One that I greatly enjoyed was a bit from The Chronicles of Narnia, based on The Silver Chair. My player characters were given the assignment of following the book characters to “watch their backs”, that is, to make sure that nothing came upon them from behind. This gave me plenty of opportunity to create adventures for them without interfering with the storyline of the book. But it also meant I had to fairly convert book creatures into game system creatures, and particularly the Narnian Giants. These are described as looking rather human, particularly in proportion; and we are given one scene in which a tall man-like creature is lying across the palm of a giant. Multiplying this out, I came to a creature who was incredibly tall. Proportionately, he was huge. When I then calculated the size bonus for attacking such a target, it was so great that it was impossible to miss, several times over, even well beyond the normal range of the weapon. I did several things to fix that. I adjusted the bonus for large targets to a quarter of what it was, and incorporated a penalty to damage (in addition to that already in place to chance of success) for attacks beyond the normal range of the weapon. But I learned something significant from that. When I later designed the Narnian Dragon (who appears by another name in The Dancing Princess), I made him much smaller–barely ten feet in height–and protected by scaly covering. It was important to make the serious enemy difficult to hit, or the amount of damage it could take boiled down to a matter of time.
The reason you can’t kill a fly easily is not that it can stand being hit, but that you can’t easily hit it. In the air, it can maneuver as fast as your hand can chase it; on the ground it can escape faster than you can close. What the fairy needed was not some huge unrealistic bonus to the amount of damage it could absorb, but a realistic appraisal of how difficult it is to hit such a creature. When I pointed this out to the group, it was very quickly resolved, bringing the damage value of the creature down to slightly above what it had been and giving it a substantial bonus as a target. Fairies in that game can survive being hit by most opponents once, maybe twice; but hitting them at all is the significant challenge.
Six [weeks months] ago when we considered Comparisons we looked at something of this idea the other way around. We perceived that in choosing a weapon, the probability of hitting the target was always a factor in the amount of damage that would be done over time. It is similarly oft overlooked that defenses of the target which reduce the ability of attackers to hit it thus multiply the value of each point of damage they can withstand. Game design is a complex mathematical process in most cases; you need to consider how each number or concept in your system relates to every other number or concept, because often the wrong fix for a problem will create more problems than it solves, and the right fix will make the entire package more logical.
[Next week, something different.]
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Next article: Plague.