Superpowers in Fear? Final Part

Possibly one of the most iconic super villains they Joker is a man of so many layers one could liken him to an onion.  No one knows for sure who Joker was before he took a swan dive into a vat of ambiguous chemicals that warped his mind, but one thing for certain is that he hasn't looked back.  While Joker is known for his many mind games with the Bat of Gotham he is most known for his iconic Joker Venom.  The gas that forces its victims to die laughing with a smile on their face.
Quite a gruesome way to go.  This could also be linked to the fear state.  The uncontrollable laughing can be chalked up to hysteria a state of extreme excitement, FEAR, and anger with the result being a combination of laughing and crying.  Victims of Joker Venom are known to do both of these things.  However, the main part of the venom is the Glasgow smiles permanently on the faces of the dead.  The result could be linked to a combo of shock and the stress of daily life.  Shock is known to have severe life threatening effects when someone is introduced to a drug their body is not accustomed to, resulting the over stress of muscles and even snapping of the spine.  Prolonged stress is said to have similar effects with the added shock to the body system the muscles could simply snap into a fatal position and leave the victim to die.  Not dissimilar to the disease known as lockjaw.