Tentacle (Half-Life)

Tentacles (sometimes referred to as Giant Tentacles) are fictional creatures from the computer game Half-Life. They first appear in the Black Mesa Research Facility, where three tentacle creatures are growing inside a rocket propulsion test chamber. They reappear later in the game, including appearances on the surface and in Xen.



Appearance
Physically, the tentacles have a bizarre appearance. A large, green, segmented stalk supports a "head," which ends in a sharply pointed, bladelike appendage and features what looks like an eye. This "eye" appears to be a sensory organ, although the creature only reacts to sound and surface vibrations, implying that the race is blind. Tentacles usually need ome sort of liquid at their base to keep them alive. Tentacles also need to live in a pit or trench. They usually emanate from pits, into which they can retract when injured or in danger. Often they make long, low frequency vocalisations, that sound somewhat similar to the songs produced by whales.

Typically several tentacles use the same pit, suggesting that they may be appendages of a larger organism. Indeed in Half-Life, after the first tentacle encounter, the player travels through the chasm the creature had occupied. The tentacle's body encountered at the bottom of the chasm is somewhat squid shaped, with three stumps that appear to have been severed. Some concept art of the tentacle shows it to be cluster of three tentacles attached to a bulbous base, which matches that encountered in the game, this also suggests that the tentacles may in fact be a kind of Alien plant. Although tentacles usually come in groups or clusters of three, single tentacles are also encountered, and the number of tentacles present may reflect the size or stage of development of the base, or else a more spread-out being, with tentacles in various locales.

There is also a notable similarity between tentacles and the Gene Worm found in Opposing Force. Similar-looking smaller tentacles, with the same blade and "eye" have also been seen in the Metroid series, often in holes in walls, retracting when injured in a similar manner.

Behavior
In terms of behavior, tentacles aggressively target prey in the immediate vicinity of their pits. While searching for prey, they gently tap the surrounding area, but when even the quietest noise or vibration is detected, the tentacles will furiously and repeatedly strike at the location where noise or vibration was detected. When a tentacle comes in contact with prey, it will attempt to pull it into the pit, presumably where it is consumed and digested. In the game, this behavior is witnessed firsthand by the player when a scientist is grabbed and taken, screaming, into the pit at the base of the tentacles.

In the game, tentacles cannot be destroyed with the player's arsenal, but shooting the stalk a few times will temporarily drive the creature into its burrow. Great care must be taken when moving near them, forcing the player either to silently crouch past the burrow or cause a distraction with explosives (preferably hand grenades, as those don't reveal the player's location with sound), allowing the player to sprint out of range.

Half-Life 2
While Tentacles do not appear in Half-Life 2, pre-release gameplay videos showed an underground battle with a Hydra, a creature similar to a Tentacle, but with blue, glowing tentacles.