Why Did Wormtail Strangled Himself?

This was Voldemort's built-in way to punish Wormtail for betraying him. The hand was given to him by Voldemort, but Wormtail owed Harry his life. When wormtail hesitated in the celler the enchantments Voldemort put on the hand kicked in and it killed him for his wavering loyalty. Kind of like the unbreakable vow.

Why did Pettigrew choke himself?

However, Harry reminded Pettigrew of saving his life four years ago, and Pettigrew released Harry in an unintended and momentary show of mercy. After Pettigrew tried unsuccessfully to undo that moment of weakness, the hand recognised Pettigrew as unfaithful to the Dark Lord and suddenly began strangling him.

Why did Wormtail kill himself?

When Lord Voldemort first started gaining power, Peter immediately defected from the Order of the Phoenix and joined the Death Eaters out of fear for his own life. ... Peter was able to escape, but for his freedom he owed Harry a life debt that would later cost him his own life.