Spell Saving Check
Some Spells allow the target to make a Spell Saving Check. To do that, they have to roll 1d20 and add their attribute modifier that is written on the Spell, e.g. if the Spell declares, they have to roll a WIL-Check, they have to roll 1d20+WIL. The value they must roll is 8 + INT + LvlB of the spellcaster.