Mage Ward

Abjuration cantrip
Casting time: 1 action
Range: Self
Target: Self
Components: V, S
Duration: 1 round
Classes: Sorcerer, Wizard
Subclasses:

You create a protective ward around yourself that strikes out at those who attack you. The first time a creature hits you with an attack before the start of your next turn, it takes 1d10 force damage and the spell ends.

The spell’s damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), and 17th level (4d10).