|“||Hey! Hey, over here! Eat lead, you outer space octopus!||„|
|~ A security guard to a tentacle|
Tentacles, are major antagonists of the Half-Life series, being large, clawed tendril-like aliens that respond violently to loud sounds.
When a Black Mesa experiment went wrong, it caused a rip in the fabric of space, teleporting several alien Xen creatures to the facility where they waged war on the facility's helpless scientists.
A trio of tentacles first appear in the rocket propulsion chamber, where they kill several of Black Mesa's employees. The tentacles only appear eight times in Half-Life and two times in Opposing Forces.