{{Enemy Infobox
| image=FileIchthyosaur.jpg|250px
| name= Ichthyosaur
| affiliation= Xen
| type=Wildlife
| health=*{{Abbr|200/200/400|Easy/Medium/Hard}}

*200 (''Half-Life 2'') (cut)
| weapons=*Claws
| entity=*monster_ichthyosaur (HL)
*npc_ichthyosaur (HL2)
| designer=*Ted Backman''Half-Life 2 Raising the Bar''
*Stephen Dennishttp//linkedin.com/in/stephen-dennis-1a84b06 Stephen Dennis on LinkedIn
{{Quote|Did you see it? They said it was hauled from the Challenger Deep, but I'm positive that beast never swam in terrestrial waters until a week ago. There's a tranquilizer gun in the shark cage, but I'm not sure it would work on this species. You're welcome to try.|Black Mesa scientist|Half-Life|Filec2a3 sci icky.ogg}}

The '''Ichthyosaur''', scientifically referred to as '''Xenotherus Icthycanthus''', is one of the many alien species that have been teleported to Earth from the borderworld 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. Perhaps the most characteristic feature of this dark green, aquatic creature is its large head with an WikipediaEpoccipital|epoccipital bone, and a mouth with sparsely growing sharp teeth. An Ichthyosaur has a several fins, a long, whip-like tail, used for locomotion, and two arms that end with a single dagger-like claw. In the concept art, the creature is said to use its limbs to pull itself along the murky bottom and to impale and hold prey. 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.

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, before falling into the ocean. Underwater, he is almost swallowed by an Ichthyosaur before being teleported elsewhere.

==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, eventually taken by the Leech) or at the lake at the start of Ravenholm, its only appearance finally being 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 Development of Half-Life 2 game|''Half-Life 2'' leak 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.

*In the WC mappack "marc" folder (referring to series' writer Marc Laidlaw) can be found a map named "ickypop". 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 Classic Zombie|Zombies are standing on a wooden bridge in the middle of a small pond. An Ichthyosaur jumps from the water and passes above the bridge, killing the Zombies and partially destroying the bridge, and then returning into the water. It jumps out of the water again and begins flying, excreting gibs while floating higher and higher to the end of the map, eventually crashing in an explosion behind a small cliff (the creature also emits its whale-like sound in the process). Above the rocks, right above where the Ichthyosaur has crashed, the G-Man can be seen fixing his tie in a loop while being held in mid-air by a flying crow. Only its tail now visible behind the cliff horizon, the Ichthyosaur starts to emanate an orange gas. 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'' leak 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.


FileIcky sculpture.jpg|Preliminary plasticine modeling.
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 early scientist.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 early scientist2.jpg|Ditto, another view.
FileIchy tiny.gif|Ditto.
FileMagazine ichy.png
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".
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''
*''Half-Life 2 Raising the Bar''


==External links==
*{{YouTube|url=OMA4ZZNVkc4|text=Video of the "ickypop" sequence}}

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