The Doctor and Rose first met a Hoix inside a warehouse where Elton Pope was almost killed by the Hoix. The Doctor saved him until Rose through hot water instead of cold water. The Hoix ran off and was assumed to have been captured by the Doctor.
There was another Hoix that appeared in a hospital. The Torchwood team sent Owen Harper to investigate. When he saw the Hoix he took the nurses cigarette's as a distraction. When Owen entered the room he threw the cigarette's down at the Hoix who then fell for the trick and was stunned. We don't know what happened to the Hoix.
There was a Hoix as part of the Pandorica Alliance along with other aliens such as Daleks, Cybermen, Silurians, Sontarans, Judoon and many others. The Alliance put the Doctor inside the Pandorica as they said he cause the crack in time. Then when he was put inside it the Universe collapsed and everything in it was wiped from history apart from the humans.
The Hoix has appeared in:
Series 2: Love and Monsters
Torchwood Series 2: Exit Wounds
Series 5: The Pandorica Opens