Transference

Using your hands to function as a medium, you completely drain a target's magic and leave them unable to cast spells permanently until either dispelled or through the usage of a wish spell. The magic you drain from the target is stored in you, and unless used before the start of your next turn, is painfully expended from you for 6d6 psychic damage. You can use the magic you steal in different ways, such as: 

Create Conduit: You can anchor the magic you've stolen in a creature you can see within 30 ft. Creatures standing within 15ft of the conduit are emboldened by the surges of magic, granting them extra potency in their spells Any spells originating within 15ft of the conduit ignore the effects of Pass/Fail and instead automatically inflict their effects. If the Target of the emboldened spell is also within the conduit, they receive an extra 4d6 psychic damage. 

Violent Expenditure: With the magic you've stolen, you can force it back into a target to cause incredible pain. Touching a creature while the magic is active causes a chain reaction. The creature touched suffers 10d6 psychic damage and each creature within 10ft suffers 4d6 as the magic surges through their bodies to find a new host. If this is used against the initial target of Transference, the magic fills the void that was originally created. the target then regains the ability to cast. 

Null Wave: Each Creature in a 30ft cone originating from the caster must make a Dexterity Saving Throw. On a fail, the target suffers 3d8 psychic damage is frightened of the caster until the start of their next turn. On a success, the target takes half damage and resists the frightened effect. 

Unpredictable Surge: At the DM's discretion, this is an optional addon to the casting of Transference, the caster and any creatures within 20ft all suffer 4d6 psychic damage or roll on the wild magic table as the weave of magic becomes unstable and behaves in strange ways. 

Only one of these effects may be used before the stolen magic is drained, and cannot be used anymore. The DM can also determine if there is a guarantee for one effect to occur, or if the effect should be entirely random.