Getting two direct-damage critical strikes in a row will make your next Pyroblast or Flamestrike spell instant cast, and cause double the normal Ignite damage.
Scored a spell critical. A second spell critical in a row will make your next Pyroblast or Flamestrike spell instant cast, and cause double the normal Ignite damage.
Your next Pyroblast or Flamestrike spell is instant cast, and causes double the normal Ignite damage.
Duration: 15 seconds
Hot Streak is a passive level 14 Firemage ability. It causes the next [Pyroblast] or [Flamestrike] to be instant cast upon getting two direct-damage critical strikes in a row, and causes double the damage from [Mastery: Ignite].
Patches and hotfixes
Patch 7.0.3 (2016-07-19): Re-added as a Fire mage passive and redesigned.
Hotfix (2010-11-23): "Pyroblast! made available by Hot Streak will no longer consume Clearcasting."
Patch 4.0.1 (2010-10-12): Now a Tier 3 and 1 Rank talent, down from Tier 9 and 3 Ranks. Your spells no longer trigger Arcane Missiles. Instead, your critical strikes with Fireball, Frostfire Bolt, Scorch, Pyroblast, or Fire Blast have a chance to cause your next Pyroblast spell cast within 15 sec to be instant cast and cost no mana.
Hotfix (2009-08-06): "Hot Streak triggers exactly as stated in its tooltip: “2 non-periodic spell criticals in a row using Fireball, Fire Blast, Scorch, Living Bomb, or Frostfire Bolt”. Only non-periodic damage interacts with it, and only those spells listed. Periodics do not affect the streak in any way. Direct damage from the listed spells always count, for or against the streak."
Patch 3.1.0 (2009-04-14): Sound has been changed (previously used the sound which played upon earning a new achievement).
[Hot Streak].
[Pyromaniac]
[Pyroblast], 
[Flamestrike]
[Mastery: Ignite].
Patch 7.0.3 (2016-07-19): Re-added as a Fire mage passive and redesigned. 
Patch 5.0.4 (2012-08-28): Removed. 
Hotfix (2010-11-23): "Pyroblast! made available by Hot Streak will no longer consume Clearcasting." 
Hotfix (2009-08-06): "Hot Streak triggers exactly as stated in its tooltip: “2 non-periodic spell criticals in a row using Fireball, Fire Blast, Scorch, Living Bomb, or Frostfire Bolt”. Only non-periodic damage interacts with it, and only those spells listed. Periodics do not affect the streak in any way. Direct damage from the listed spells always count, for or against the streak." 
[Living Bomb]. 
