Pokémon Red Version, Blue Version, and Yellow Version - Descriptions of Common Effects
Effects that are common to many attacks are described below. Of the effects listed here, a Pokémon will remain poisoned, burned, paralysis, frozen, and asleep even when the Pokémon leaves the battle, including when a battle ends. (However, a Pokémon will stop being poisoned, burned, paralyzed, frozen, and asleep, as well as have full HP and PP, when it’s taken to a Pokémon Center nurse, but not when it’s placed in a PC storage box.) An effect can’t cause poison, burn, paralysis, freezing, or sleep against a Pokémon if it already has one of these five conditions or if it has fainted.
Poison (PSN)
If a Pokémon is poisoned, it loses 1/16 of its maximum HP (but not less than 1 HP) at the end of its attack segment. Poison types can’t become poisoned, not even by Twineedle. Outside of battle, a poisoned Pokémon loses 1 HP every four steps the player walks. (The effect of Toxic is similar to poison, see " Toxic ".)
Paralysis (PAR)
When a Pokémon becomes paralyzed, its Speed is recalculated so that it is reduced to 25% (see the section "Stat Stages"). If a Pokémon is paralyzed, there is a 25% chance that it will lose its chance to attack. Ground-type Pokémon can’t become paralyzed by Electric-type attacks.
Burn (PSN)
When a Pokémon becomes burned, its Attack is recalculated so that it is halved (see the section "Stat Stages"). If a Pokémon is burned, it loses 1/16 of its maximum HP (but not less than 1 HP) at the end of its attack segment. Fire-type Pokémon can’t become burned.
Sleep (SLP)
A sleeping Pokémon can’t choose any moves. When a Pokémon becomes asleep, it receives a count of 1 to 7 (or 1 to 3 in Pokémon Stadium (known as Pokémon Stadium 2 in Japan)). At a sleep check, this count is reduced by 1. If the count reaches zero, the Pokémon wakes up, but can’t attack on the same attack segment. The game stores the current duration of a Pokémon that’s asleep, in case the Pokémon leaves battle and enters the battle in another one.
Frozen (FRZ)
A frozen Pokémon can’t choose any moves. Use of Haze or Fire-type moves by the opposing Pokémon will cure freezing. Ice-type Pokémon can’t become frozen. If the Pokémon didn’t strike first and was defrosted by fire, it will use the last move chosen for use if possible, even if that move has zero PP. (If the move is used this way and it has 0 PP, the game erroneously subtracts 0 by 1, resulting in the value 255 (that is, 256 minus 1, wrapping around to 8 bits), or 63 PP (low 6 bits) and 3 PP Ups used (high 2 bits).)
In Pokémon Stadium (known as Pokémon Stadium 2 in Japan), it is possible to choose a move while the Pokémon is frozen.
Confusion
When a Pokémon becomes confused, it receives a count of 2 to 8. At the beginning of the Pokémon’s attack segment, this count is reduced by 1, then if it is greater than 0, there is a 50% chance that the Pokémon will deal damage to itself rather than use an attack. The self-inflicted confusion attack is a physical attack, has a power of 40, has no type, is not varied with a random number, and ignores the effect of Reflect. (The attack can be a critical hit.) Confusion is removed from the Pokémon when it leaves the battle.
In Pokémon Stadium (known as Pokémon Stadium 2 in Japan), messages concerning confusion are displayed after the message concerning the move to be used.
Flinch
After another Pokémon uses a move that causes a Pokémon to flinch in the same turn, it skips its attack this turn. A Pokémon can’t flinch if it is asleep or frozen.