A creature that can hear you within range must succeed on a DC 13 charisma saving throw, or have disadvantage on all attack and damage rolls against you until the start of their next turn. Roll a d10. If you roll a 10, the creature is also frightened. This is optional if you want to lower the amount of dice being rolled at once. In addition, you may add to the number of targeted creatures by adding one item to the "boasting list". It has to be something the DM thinks would impress the creature.
Additionally, you may... bend the truth a little. If you lie about these events/accomplishments, you have to your deception against the creature's insight. If they roll higher than you, the spell ends, and any creatures previously affected by this spell lose the disadvantage on attacking you, and instead gain advantage, as they now think you lied about everything.
The maximum number of creatures affected by this spell is equal to the level of spell slots used added to your magic user level. Once a creature has been affected by this spell, the creature cannot be affected by the same accomplishment from the boasting list, or any that they have heard previously.