Tarmuid's Sigil

You draw an arcane sigil on the body of a willing creature within 5 feet of you, bolstering its natural offenses. The creature can be yourself. Until the spell ends, when the creature hits a target with an Unarmed Strike and deals damage, the target takes an extra 5d4 Force damage.

In addition, once per turn when the creature hits a target with an Unarmed Strike and deals damage, the target is pushed 10 feet directly away from the creature or has the Prone condition (the creature's choice).

When the spell ends, the sigil disappears.

Using a Higher-Level Spell Slot. The damage increases by 1d4 for each spell slot level above 5.