Fortune’s Shield

1st-level abjuration

Casting Time: 1 bonus action

Range: Touch

Components: V, S, M* (a rabbit’s foot)

Duration: 1 hour

You create a shield that shimmers into existence in front of you. This shield grants you the blessing of luckiness. Whenever a creature makes an attack against you, roll a d20. If you roll an 11 or higher, your AC increases by 1d4 until the start of your next turn. If you roll a 10 or below, nothing happens. If you roll a 1, your AC decreases by 1d4.

Likewise, whenever you have to make a saving throw, roll a d20. If you roll an 11 or higher, roll a 1d4 and add it to the saving throw. If you roll a 10 or lower, nothing happens. If you roll a 1, roll a 1d4 and add that to the DC of the saving throw.