The Tentacle's body appears to be a long, segmented green stalk with its head ending in a large blade-shaped appendage. While its head does possess an eye, it does not seem to respond to visual stimuli and has only been seen reacting to sound and vibrations.
When a Tentacle detects any nearby noise, it will lash out with its blade at the sound's source, swiftly butchering any living thing that treads through its lair without being completely silent.
The Tentacle cannot be killed by any weapon in the player's arsenal, but can be briefly stunned. It can also be distracted by utilizing grenades, throwing them afar and allowing the explosion to get the Tentacle's attention.