Sapping Spell

Increase spell damage by rolling Hit Dice, taking half the result as damage.

Classes
Sorcerer

You can increase the damage you deal with a spell by expending 2 sorcery points and up to half your remaining Hit Dice. Roll the Hit Dice and add the total result to the damage dealt by the spell. You then take damage equal to half the amount of damage your Hit Dice added to the spell’s damage.

Source and licence

From Tome of Heroes.

Licence: Open Game Content (OGL 1.0a).

Every licence notice Tavern Bag relies on.