Elan Vital Interrompre

This cantrip can take a pool of magical energy that guards the lifeforce and use it to temporarily distort the lifeforce of another.  

The caster can use their temporary hit points to lessen a save, attack roll, ability or skill check by the amount of temporary hit points in the caster's pool. 

So a temporary hit point pool of 4hp could be used to inflict a -4 to a roll of the casters choice.  It must be used in the instant it is cast. The amount of temporary HP that is announced is consumed.  If the target makes an intelligence save, the temporary hit points are lost and the cantrip is ineffective.