Chain Reaction

Chains shoot out of you in a 20 foot cube, everybody within the range must make a DC12 Dexterity saving throw or take 1d8 bludgeoning damage, half as much on a successful save, and will obtain the restrained condition.

A creature can use there turn to try to escape the chains, to do this they must make a Dexterity saving throw, if they succeed, they are freed and they're turn is finished.