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This article is about the recreational narcotics used by Unggoy. For the gel used by the Forerunners and Covenant for energy, see infusion gel.
Poisoned infusion gas in the lower districts of High Charity

Evan Phillips: "What's infusion?"
Dengo: "It smoothes the day out."
Evan Phillips and Dengo[1]

Infusions are recreational narcotics used by the Unggoy, who add them to their portable methane tanks[1][2] or suck on them from a tube.[3]

In 2462,[4] as a revenge for Kig-Yar nest relocations on High Charity caused by the rapidly increasing Unggoy numbers, some radical Kig-Yar shipmasters poisoned Unggoy infusion supplies, making several thousand affected Unggoy males sterile. The Covenant leadership's lack of response to this event, which became known as the "Infusion Incident", eventually caused the Unggoy to revolt, beginning the Unggoy Rebellion.[2]

Dengo was a user of infusions as it helped pass the time while he worked in the fields of Nes'alun keep, Sanghelios.[1]


The Final Grunt in Halo 3 says "When I'm on the gas, I don't know what I'm doing half the time!". The "gas" may be referring to a type of infusion.

List of appearances[edit]


  1. ^ a b c Halo: The Thursday War, pages 186-187
  2. ^ a b Halo: Contact Harvest, pages 150-151
  3. ^ Halo: Mortal Dictata, page 222
  4. ^ Halo Encyclopedia (2009 edition), pages 115 and 142