Stellaris Phantasm (5e Spell)
From D&D Wiki
The caster summons water around themselves, emulating the starry skies before letting forth a burst of energy. Choose a number of creatures equal to your spell-casting modifier. They must make a Constitution saving throw or be trapped within an illusionary bubble and take 4d8 force damage. Creatures who pass their saving throw are not trapped within the illusionary bubble and take no damage but immediately have an omen applied to them. Enemies trapped inside this illusionary bubble are restrained for 1 round as a constellation-like marking appears on the bubble and they are soaked. After 1 round has passed or the creature is damaged by an allied creature, the bubble bursts, freeing the trapped creatures but applying an omen on them. When a creature has an omen applied to them, they visibly emit a purple aura. For the next minute, each time they take damage, they will take additional damage equal to the total amount of damage die dealt or 3, whichever is higher. For example, an 8d6 fireball will become 8d6+8. If no damage die are present when taking damage, they instead take damage equal to the spell tier of this spell. If an allied creature attacks, they burst the bubble, causing their attack will instead deal double damage in addition to prematurely bursting the bubble.