ill change my request then,
Name: Soul Strings
Mana cost: 25% of the targets maximum health.
Targets allowed: Enemy, units,summons, non-hero
Effect: allows the caster full control over the target unit, if the caster is attacked while the unit is controlled the spell will break and the unit will go back to its original owner
if 60 seconds pass and the caster has not been harmed an additional 25% of the targets maximum health of mana will be used to keep the unit permanently.
additionally if the unit is a summon it will only take 30 seconds to take control and the summons duration will be removed allowing the summon to last indefinitely
edit: I'd also want it to be able to cast on other units when i casted it previously, each consecutive cast while a unit is not completely control will reset the time to 60 even if the next unit is summoned.