Tixan's Lightning Shackles

You create a chain made out of lightning and sent it towards any creature in your range. Target takes 5d8 lightning damage. After this, targeted creature must succeed on a Dexterity saving throw, or become [condition]restrained[condition/] for 1 minute. Target can make a new Dexterity saving throw at the end of their each turn to break free of the lightning shackles. 

At Higher Levels. When casted with a 5th level spell or higher, targeted creature takes an additional 1d8 lightning damage for each slot above 4th level.