{{Enemy Infobox
| image=FileIchthyosaur.jpg|250px
| name= Ichthyosaur
| affiliation= Xen
| type=Wildlife
| health=
| weapons=Claws, teeth
| entity=*monster_ichthyosaur (HL)
*npc_ichthyosaur (HL2)
| designer=Ted Backman''Half-Life 2 Raising the Bar''
{{Quote|I'm sure that beast never swam in terrestrial waters until a week ago!|Black Mesa scientist|Half-Life}}

The '''Ichthyosaur''' (taxonomic designation ''Xenotherus icthycanthus'', or "Spined Alien Fish Beast") is an alien species transported to Earth from the Border World, Xen. Prominently featured in ''Half-Life'' and its expansions, it has a small cameo at the start of ''Half-Life 2''.

FileC2A3ICKY.png|192px|thumb|left|In ''Half-Life Opposing Force'', a wall poster depicts the creature's skeleton with the title "Xenotherus Icthycanthus".

Although it is named after the extinct marine reptile group, the WikipediaIchthyosaur|Ichthyosaurs, it resembles them only in its carnivorous ecology and its general size. When the Ichthyosaur is first encountered in the ''Half-Life'' chapter ''Apprehension'', a scientist remarks that while he has been told it was hauled from the WikipediaChallenger Deep|Challenger Deep in the Pacific Ocean, he is of the opinion that the creature never swam in terrestrial waters until a week before, possibly the time of its arrival at the Black Mesa Research Facility, the creature being likely from Xen. However, there is evidence that Ichthyosaur specimens were kept for observation as seen in Opposing Force.  

In ''Half-Life'', Ichthyosaurs are encountered in several water bodies, including a flooded laboratory, the reservoir behind a hydroelectric dam, in the sewage areas and in one of Nihilanth's chambers. They are often placid at first, but quickly become hostile, especially should the player take action against them. The speed and viciousness of the Ichthyosaur combined with poor underwater visibility make the underwater areas of ''Half-Life'' some of the most frightening parts of the game.

The Ichthyosaur also makes a single appearance in ''Half-Life 2''. During a teleport malfunction ("harmonic reflux"), Gordon Freeman is momentarily transported outside of City 17, in midair. He looks down, and falls into the ocean. Underwater, he is almost swallowed whole by an Ichthyosaur before being transported elsewhere. Although this encounter is scripted, when an Ichthyosaur is spawned using console commands or a mod such as ''Garry's Mod'' it also attacks the player in the same manner, suggesting that the developers planned on Gordon Freeman encountering them in the game proper.

==Behind the scenes==

FileIcky concept.jpg|250px|thumb|right|Concept art.

*The Ichthyosaur was originally referred to as "Muddy".

*Strong art direction and clear goals were set for the Ichthyosaur from the start, but the AI proved to be very complicated due to the size of the creature and how different it was from the more common game monsters of that time.

*The Ichthyosaur was to appear more prominently in ''Half-Life 2'', such as in the the Coast levels where he was to fulfill the role of keeping the player from venturing too far into the ocean. However, this was eventually replaced by the Leech)and there is no Ichthyosaur encountered at the lake in the start of Ravenholm, its only appearance is in the recycled Ravenholm lake seen during the teleportation failure at the start of the game.WC mappack

*The Ichthyosaur can be encountered in the playable Half-Life 2 Beta|''Half-Life 2'' Beta in several The Coast|coastline maps (such as "d2_coast_02", among others), where it takes the role of the Leech, i.e. keeping the player from venturing too far into the ocean. If the player swims out too far from the land, an Ichthyosaur can be heard and a few seconds later the player dies, while the creature cannot be seen. Interestingly, the Ichthyosaur sounds are named "ping1.wav" and "ping2.wav". This could suggest that the Ichthyosaur detects its prey in a manner similar to sonar.

*In the playable ''Half-Life 2'' Beta texture folder for the Bullsquid can be found a texture file called NewBullsquidSheet.vtf, which is actually an alternate skin for the Ichthyosaur. It is also signed by Ted Backman and dated 2003, in his stylized signature.Playable Half-Life 2 Beta|''Half-Life 2'' Beta files

*In the WC mappack "marc" folder (referring to series' writer Marc Laidlaw) can be found a map named "ickypop.vmf". Based on an old version of the Ravenholm docks where an Ichthyosaur was to be found, the map consists of a surreal/nonsense sequence three Standard Zombie|Zombies are standing on a wooden bridge in the middle of a small pond, then an Ichthyosaur jumps from the water and passes above the bridge, killing the Zombies and partially destroying the bridge while doing so. Then the Ichthyosaur returns into the water, then jumps out of it again and starts flying, excreting gibs while flying higher and higher to the end of the map, to crash in an explosion behind a small cliff (the creature also does its whale-like sound while crashing). Above the rocks, right above where the Ichthyosaur has crashed, can be seen the G-Man held in mid-air by a flying crow, who starts fixing his tie in a loop after the creature has crashed. While only the Ichthyosaur's tail can be seen under, it starts eructing an orange gas at the G-Man. The sequence is accompanied by two instrumental tracks, one mysterious (that plays through the all sequence in a loop), another faster-paced (that plays only when the Ichthyosaur first appears), found in the folder "/scripted/stinger/" in the playable ''Half-Life 2'' Beta sound files. They were taken from the ''WikipediaAliens (film)|Aliens'' soundtrack (dialogues from the film to be used for the maps "aliens_test" and "testroom_ripley" can also be found in the sound files). After that everything remains the same in a loop. Given the sequence, it is possible that the map name was misspelled and normally named "ickypoop". This recalls the scene at the start of the ''Half-Life 2'' chapter ''The G-Man 2 2|Anticitizen One'' during which the G-Man can be seen on a television screen with a crow on his shoulder. "Ickypop" may be a test map for that sequence.

*When killed in ''Half-Life 2'', they freeze due to having no death animation nor a physics model.

*It is possible to lure the Ichthyosaur out of the water in Sector G Hydro Electric.

*If the Ichthyosaur is killed in ''Half-Life'' (GoldSrc version), the player can stand on its body as the body is solid. However, one should avoid to jump on the body if the player falls from great height as this can injure or kill the player.

*The ''Half-life 2'' version of the Ichthyosaur appears in the mod Black Mesa Source, it has fixed waypoints and animations.

*The auto-aim cannot locate the Lchthyosaur when they are fully underwater while the player is outside the water, this is possible to prevent cheating.



FileIcky sculpture.jpg|Preliminary plasticine modeling.
FileIcky artwork.png|Artwork.
FileIcky old promo.jpg|Ichthyosaur early promotional image. ''"If you were this ugly and smart enough to know it, you'd feel like killing someone too."''
FileIchthyosaur beta scientist Half Life.jpg|Ichthyosaur attacking a scientist in an early version of the CenCom Reservoir. There are no scientists there in the final version; that scene was moved to Sector E's industrial area.
FileIchthyosaur beta scientist2.jpg|Ditto, another view.
FileHL BMRF Waterplc.jpg|The Ichthyosaur lurking below a cage.
FileIchthyosaur hl1.jpg|''Half-Life'' model.

===''Half-Life 2''===

FileIckypop zombies.jpg|The Ichthyosaur jumping at the Zombies, in the map "ickypop".
FileIckypop0010.jpg|The Ichthyosaur right after killing the Zombies and destroying the bridge, in the map "ickypop".
FileIckypop gibs sky.jpg|The Ichthyosaur excreting gibs while flying, in the map "ickypop".
FileIckypop gman crow.jpg|The G-Man and his crow, in the map "ickypop".
FileIckypop orange gas.jpg|The Ichthyosaur spreading orange gas towards the G-Man and his crow, in the map "ickypop".
FileNewBullsquidSheet.jpg|''Half-Life 2'' Ichthyosaur alternate skin, signed by Ted Backman. 
FileIchthyosaur.jpg|''Half-Life 2'' model.
FileIchthyosaur_teleportation_failure.jpg|The Ichthyosaur rushing at Freeman during the teleportation failure.

==List of appearances==

*''Half-Life'' {{1st}}
*''Half-Life Opposing Force''
*''Half-Life 2'' (Cinematic only)
*''Half-Life 2 Episode One'' {{Gf}} {{Nc}}
*''Half-Life 2 Episode Two'' {{Gf}} {{Nc}}


==External links==
*{{YouTube|url=CrPc_ML70Xc|text=Video of the "ickypop" sequence}}

CategoryXen creatures
CategoryHalf-Life Opposing Force
CategoryHalf-Life 2
CategoryTed Backman designs

|description=The Ichthyosaur.
|source=''Half-Life 2''
|other versions=
|cat artist=
|cat subject=CategorySource model imagesCategoryIchthyosaur images
|cat type=CategoryHalf-Life 2 screenshots