Grip of Iron

You have learnt the art of never letting go, your Grip is a nigh inescapable Prison.

• While your grappling someone, if they attempt to use any means to teleport away you may try to interrupt the attempt as a reaction, roll a contested Strength check, if you succeed the attempt to teleport Fails, if your opponent succeeds the attempt resolves as normal.
  
  
• While grappling someone you may use an action to begin choking them.

  If the creature requires air to breathe, it begins to suffocate. This continues until the creature is no longer grappled by you. A suffocating creature can survive for a number of rounds equal to 1 + its Constitution modifier (minimum of 1 round). At the start of its next turn after those rounds are over, it becomes unconscious, and it can’t regain hit points until it can breathe again.