This site is games | books | films

Thunderstone Bomb

Ultimate Equipment Guide II

Author Greg Lynch, J. C. Alvarez

Publisher Mongoose Publishing

Publish date 2005

It is usually assumed the thunderstone bomb is simply one enormous thunderstone. Or, failing that, that it is simply a normal bomb filled with thunderstones that detonate together at the point of impact. The second supposition is closer to the truth, but the actual design of the thunderstone bomb is more ingenious than that. The bomb carries a payload of two dozen thunderstones, all wrapped in cotton batting. The thick cotton absorbs enough of the kinetic energy of the bomb blast to prevent the thunderstones from detonating along with the bomb’s alchemist’s fire core. The thunderstones are expelled from the explosion like shrapnel, fired outward at a colossal speed, their cotton cocoons burned off in a blink of an eye by the intense heat of the explosion. By the time the thunderstones have travelled five feet from the point of detonation, the cotton surrounding them has been burned and blasted enough that it is no longer effective in protecting the thunderstones from direct impact. Each thunderstone is expelled in a random direction (Games Masters should roll 1d8 to determine the path each thunderstone follows), travelling anywhere from ten to 50 feet from the point of impact.

A thunderstone passing through an occupied square has a 50% chance to strike the creature or object in that square, detonating as it does. Such is the speed at which the thunderstones are travelling that any creature hit by one will take 1d6 hit points of damage from the impact, in addition to the possibility of being deafened by the thunderstone. A thunderstone that does not hit a creature or object will usually detonate when it strikes the ground at the end of its ten to 50-foot journey. However, as a general rule of thumb, any given thunderstone has a 25% chance of not detonating when it hits the earth. Games Masters may feel free to adjust that percentage up or down depending on the consistency of the ground struck by the thunderstone (in muddy conditions, it may be as high as 50%, while on a barren expanse of rock, it may be as low as 10%). Used effectively on a massed enemy, the thunderstone bomb could conceivably render every enemy within 60 feet of the point of the bomb’s detonation deaf.

Thunderstone Bomb: 800 gp; 45 lb.

Scroll to Top