The Beast Within (Lycanthrope 1)

When you drop to 0 hit points, the beast comes out to fight

• If the character drops to zero hit points,
  an immediate transformation will occur even if the number
  of transformations per long rest has already been reached.
• The Lycanthrope gains 8d8 temporary hit
  points.
• Only Claw and Bite Attacks can be performed, no class actions
• On each turn after transforming, the werewolf must
  either attack or be attacked to maintain the transformation.
  After one minute- or if the werewolf fails to attack or be
  attacked- it reverts to its true form at zero hit points and
  begins making death saves if necessary.