Tel's Tranquil Composure

You focus on a creature that you can see, silently studying them and charging up a forceful blast. Its potential increases exponentially the longer you charge it. For the following 2 turns of combat after the spell is cast, you can either continue to charge it up or you can release the spell as a bonus action. Before releasing it, you can only move, otherwise, the spell fades. It also fades if you speak. Upon release, a swirling white translucent blast strikes the creature, which must succeed on a CON saving throw or take damage and effects determined by how many rounds of combat have passed following the casting of the spell. On a success, the creature takes half damage and no effects are applied.

• When cast: 3d8 force damage and the target is pushed 10ft away from you
• 1 round after casting: 6d8 force damage and the target has disadvantage on all attacks until your next turn
• 2 rounds after casting: 10d8 force damage and the target becomes stunned until the end of your next turn

If you end your turn and cannot see a targeted creature OR if the spell is not released within 2 rounds, it spell backfires. You must succeed on a CON saving throw (DC 12) or be knocked prone. For every 2 spell slots above 3rd level, you can target one additional creature.