Headcrabs are mysterious creatures which dwell in the chat tower, and have the power to make chatters vanish mysteriously into thin air. Their existence can activate Kat's "chicken" mode, in which she yells out "bregak!" and runs around the room senselessly like a headless chicken.
Several headcrabs attempted to gain a Route 50 account named Wired, but were quickly identified by Kat as "Crab People" and were deleted shortly thereafter.