This spell has a duration of one short rest. You can target either yourself or another creature:

Self: You gain 8 hours of time to research or add spells to your spellbook.

Other: Target creature takes 10d8 necrotic damage as they are aged significantly by a time vortex. They get to make a dexterity saving throw. If they succeed, they take half damage, otherwise, they age 10d8 years, which impacts them physically.

Higher Levels: Add 2 hours per additional level for self casting, or 2d8 per spell level damage for targeting another creature.