Freezing Jackal
From Halopedia, the Halo wiki
To see a Jackal Freezing on Outskirts, you must play Outskirts on Legendary until you get to Sniper Alley.
Get a Sniper Rifle or Beam rifle then shoot the Jackal that walks into the open in the chest. Usually he freezes and draws a Plasma Pistol but very rarely dies frozen in midair if you shoot its head. Occasionally, while he is frozen, he will shoot you with the Plasma Pistol.
