Serious Sam 3: BFE

Copy protection

Rather than disabling the game to users of pirated releases of the game, Croteam took a more creative approach to copy protection. If the game turned out to be illegally copied, a blazing fast arachnoid would appear after killing the first enemy. The arachnoid is completely invincible and follows the player around until he kills him.

In addition, the level Under the Iron Cloud was programmed so that, should the game be pirated, Sam was forced to look up to the air and spin, unable to fight any enemies who would approach him.