Sigil of tempest
Sigil of tempest is a technique in SLASH'EM. When used, it creates 3x3 explosions around you centered in a 7x7 area (excluding the 3x3 area around you, so you will not be hit) instead of firing a ray. This technique affects all ray-based spells except finger of death.
When used with sigil of discharge, the number of explosions doubles.
Most ray-based spells in SLASH'EM, as well as fireball explosion, use six-sided damage dice. It seems sigil of tempest explosions were supposed to deal (XL/4 + bonus)d6 damage, however, due to what is probably a bug, they do only plain (XL/4 + bonus) damage, resulting in single digit damage in most cases, making the technique mostly useless.