The Bomb Spell is a passive item found in Momodora III.
Equipping this item will make your paper seal charge attack explode if they either hit an enemy or travel the maximum distance. Since every charge attack in the game ignores walls, certain enemies can be shot through them.
The Bomb Spell can't be effectively combined with another item, but avoid using it with Marine's Symbol, since the fireball charge attack has endless range and travels through opponents instead of fading on hit. It will therefore never explode on screen, making the Bomb Spell useless.