The Ichthyosaur was originally intended to fulfill the role of keeping the player from venturing too far into the ocean.

In Half-Life 2, they cannot be killed and will drain the player's health in a matter of seconds.

In Half-Life, Leeches are minor enemies that do not cause much damage and can be easily killed.

He also states that their population is kept down by seagulls and that they ate most of the crabs.

Since ocean fish are now very rare or extinct, the human occupants of coastal areas seem to catch and eat Leeches instead. Furthermore, the Fisherman reveals that Leeches are used as food. In Lost Coast, Leeches behave like in Half-Life 2. Here the eye count is brought to only two. In Half-Life 2, they attack Gordon Freeman in a swarm (an attack similar to that of the terrestrial piranha) if he ventures too far into the ocean, to prevent the player from venturing to the 'end' of the map and force them to follow the proper path (much like the chopper in the video game Far Cry, for instance). In addition to being teleported to Earth, they are kept in the Black Mesa Biodome Complex for study. Leeches make their first appearance in Half-Life in some of the flooded sections of the Black Mesa Research Facility after the Resonance Cascade. Leeches in an aquarium in the Biodome Complex. While leeches are commonly seen in freshwater bodies, Ichthyosaurs also seem to occupy freshwater bodies as well, possibly showing non hostile coexistence between Xen fauna. Despite this, statements made by the fisherman say that Earth creatures such as seagulls have turned to hunting them, as it is stated that they keep their numbers down (as there may not be much for the seagulls and other predators of the leeches to eat in the first place due to the leeches themselves). Some Earth creatures remain in inland bodies of water, where insects and frogs can be heard (though it is likely that their numbers have also been heavily reduced by the leeches, much like the crabs). Indeed they are the only creatures commonly seen in water bodies (though in series during the second game, we only mostly see them in the sea), though it is said that some creatures may remain, mostly crabs, though their numbers are said to have been heavily reduced by the leeches. They seem to have successful in establishing themselves, to the point that they may have caused the extinction most, if not all, of freshwater and marine fauna.

They are usually white (sometimes pink or yellow) in color.ĭuring the Resonance Cascade, Leeches were teleported to Earth, infesting freshwater and saltwater bodies.

They also resemble lampreys, hagfish, and candirus, and are similar to those animals in ecological niche as well. Leeches appear as small, agnathan like creatures that resemble leeches, specifically the terrestrial medicinal leeches.

Half life sea monster