Xen Tree

The Xen Tree or simply Tree is apparently a smaller relative or the stalk of the Half-Life boss creature, the Tentacle (although it has not been confirmed), and a native plant of the border world Xen. Xen Trees are around thirteen to sixteen feet tall, brownish tree-like creature with no leaves or branches, a fully mobile "trunk", and a large, hook-like appendage at the top, used for attacking nearby prey.

Xen Trees are scattered around the Xen and can prove a danger to unwary players and Xen wildlife by violently stabbing at any nearby source of movement.

Physiology and lifestyle
Xen Trees appear to be carnivorous, like their possible larger relatives. They attack nearby enemies so as to kill them and probably allow their bodies to decompose onto the surrounding ground, the nutrients from this process effectively feeding the Xen Tree. They are often found near Xen's Light Stalk plants, and though it is possible this is a coincidence, it may also be a kind of mutual symbiosis; the light from the stalk attracts prey, then the Xen Tree kills it, feeding both plants.

List of appearances

 * Half-Life
 * Half-Life: Opposing Force
 * Half-Life: Blue Shift