Some games humorously penalize the player for using another game's cheat codes. For example, using cheat codes from "Doom" in "Descent" only displays sarcastic messages from the programmers on screen; using codes from "Descent" in its sequel "Descent II" lowers the player's shields and energy to 1%. Codes from "Doom" used in "Heretic" give the opposite of the desired effect, such as instant death instead of invulnerability or stripping weapons instead of providing them. The original "Doom"s "god mode" code "IDDQD" is non-functional in "Doom 3", but produces a console message: "Your memory serves you well."