Finger of Fate

Cantrip (divination; chaos)
Class(es): Bard, cleric, sorcerer, warlock, wizard
Casting Time: 1 Reaction
Range: Medium (60 feet)
Target: One creature
Components: V, S
Duration: Instantaneous

When you see a creature making a saving throw, an ability check, or an attack, you point at it and whisper words of good luck. The target must succeed on a Wisdom saving throw, or it will have disadvantage on its current saving throw. If the creature succeeds on the saving throw, it has advantage on its current saving throw instead.