A "hijacked netblock" is a netblock brought back from the dead, often by a spammer, also called a "zombie netblock." (The term "zombie" later became widely applied to the infected PC drones in a botnet.) The original owner of the block may have left it derelict for any number of reasons. Squatters then reclaim it with various ploys including registering an abandoned domain name to accept email to the point-of-contact domain contact, or printing up bogus letterhead, or doing a bit of human engineering over the telephone. Some hijackers even outright steal IP-space allocated to someone else just by announcing it under their BGP Autonomous System Number.