Minecraft wiki entry for Hitboxes, associated text: Breaking this line of sight can be done in a variety of ways. The first way is to place blocks between the player and the mob, thus preventing you from seeing the other mob's red rectangle. Most mobs cannot see through glass, so it can be used for these purposes. Another solution is to get out of range of the mob, so that it does not attack you. This is difficult to do for long-distance attackers, such as Blazes. Another solution is to kill the mob or unload the chunks that contain it.