A new Brutality has been discovered for Jax in Mortal Kombat 11. You can see the Brutality in action via the video above, but longtime fans of Mortal Kombat might recognize it as a callback to the earlier days of the franchise.
All the way back in Mortal Kombat 3, Jax had a Fatality where he would grow super huge, and then squash his opponent with his boot. There's no doubt this Brutality is a callback to that. The only issue right now is that players are unsure on how to unlock the Brutality. The best guess puts it as a reward in the upcoming Towers of Time event.