Dynamic A.I

[Googolplex]

The Alien also adapts. After evading it successfully enough times, it will begin to behave like an ambush predator. Waiting in the vents, you can sometimes see its sick silicone drooling seeping out. It waits for you to make the wrong move, to come closer.

This is unscary for me. When a monster is waiting for you it seems like a fun-challenge and no longer increasingly serious. When the monster plays "catch me if you can" with the player, it is acting like a human and this means a bad designed A.I. (even when it might be more dynamic).