also: fire zone
Sending an extra rusher while dropping someone unexpected, usually a defensive lineman, into the space the rusher left.
Pressure in which the defense brings extra rushers from one area and replaces the vacated space with a defender the offense did not expect to drop, most often a defensive lineman. Coverage behind it stays zone. The deception is about who rushes and who drops, not about the number of rushers.
fire zone, zone pressureman blitz, bluffThe reason it works is the offense's own answer to pressure. A quarterback reading blitz throws hot into the grass he believes the rusher left, and against a fire zone somebody is standing in exactly that grass. The scheme is aimed at the hot throw specifically, rather than at the protection.