Backstab

You catch your enemy unawares as they attempt to move away from you.

When you take the Attack of Opportunity reaction, you may choose to take a -5 penalty to the attack roll. If the attack hits, add +10 to the damage roll. Additionally, that enemy's speed is slowed by 10 feat until the end of their next turn.

This feat may only be used with light weapons, weapons with the Finesse property, or, if you have the Dual Wielder feat, any One-Handed weapon.