Summon a number of tiny ghost like entities equal to your Int. modifier within 30 ft. of you. You may have each of them latch onto separate creatures or all onto one creature. Any creature that is affected by an entity has movement speed reduced by half and hit point maximum reduced by your Int. modifier for each ghost attached.
As a bonus action on each of your turns you may have one of the entities or all of them detonate. When the entities detonate it causes the affected creature to have a negative 1 modifier per ghost to their next saving throw and disadvantage if all ghost detonate simultaneously which ends concentration of this spell. At the end of the affected creatures turn it may make a constitution saving throw to attempt to end the effects on them.
* - (Ectoplasmic Residue)