Secret Power

Deals damage and has a 30% chance to inflict a status effect which depends upon the terrain.

Secret Power deals damage and causes a variety of different secondary effects depending on the current terrain.
Secret Power also changes its own animation to another move depending on the terrain.
The list of secondary effects of Secret Power varies highly by generation:

Gen 3

Terrain	Secondary Effect	Move Animation
Building and link battle	paralysis	Strength
Plain terrain	{paralysis;STATUS;paralysis}	Slam
Sand	lowers accuracy by one stage.	Mud Shot
Cave	flinching	Bite
Rock	confusion	Rock Throw
Tall grass	poison	Needle Arm
Long grass	sleep	Magical Leaf
Pond water	lowers Speed by one stage.	Bubble Beam
Sea water	lowers Attack by one stage.	Surf
Underwater	lowers Defense by one stage.	Waterfall

Pokémon Colosseum and Pokémon XD

Terrain	Secondary Effect	Move Animation
Buildings, The Under Subway, Realgam Colosseum Mt. Battle (Areas 1-3), S.S. Libra	{paralysis;STATUS;paralysis}	{Needle Arm;MOVE;needle-arm}
Outskirt Stand, Phenac City, Cipher Lab (outside)	lowers {accuracy;STAT;ACCURACY} by one stage.	{Needle Arm;MOVE;needle-arm}
Pyrite Town, The Under, Cipher Key Lair (outside), Citadark Isle (outside), Rock Poké Spot, Pyrite Colosseum, Mt. Battle (Areas 7-10)	{confusion;STATUS;confusion}	{Needle Arm;MOVE;needle-arm}
Phenac Stadium	lowers {Defense;STAT;DEFENSE} by one stage.	{Needle Arm;MOVE;needle-arm}
Agate Village, Relic Stone, Mt. Battle (outside), Pokémon HQ Lab, Kaminko's House, Mt. Battle (Areas 1-3)	{poison;STATUS;poison}	{Needle Arm;MOVE;needle-arm}
Relic Stone	{sleep;STATUS;sleep}	{Needle Arm;MOVE;needle-arm}
Pyrite Cave, Relic Cave, Deep Colosseum, Mt. Battle (Areas 4-6), Cave Poké Spot	{flinching;STATUS;flinch}	{Needle Arm;MOVE;needle-arm}
Gateon Port	lowers {Attack;STAT;ATTACK} by one stage.	{Needle Arm;MOVE;needle-arm}
Oasis Poké Spot	lowers {Speed;STAT;SPEED} by one stage.	{Needle Arm;MOVE;needle-arm}

Gen 4

Terrain	Secondary Effect	Move Animation
Building and link battle	{paralysis;STATUS;paralysis}	Body Slam
Distortion World	{paralysis;STATUS;paralysis}	Pound
Sand, plain terrain and puddles	lowers {accuracy;STAT;ACCURACY} by one stage.	Mud Slap
Cave and rock	{flinching;STATUS;flinch}	{Rock Throw;MOVE;rock-throw}
Grass	{sleep;STATUS;sleep}	{Needle Arm;MOVE;needle-arm}
Water	lowers {Attack;STAT;ATTACK} by one stage.	Water Pulse
Snow	freeze	Avalanche
Ice	{freeze;STATUS;freeze}	Ice Shard
Marsh	lowers {Speed;STAT;SPEED} by one stage.	{Mud Shot;MOVE;mud-shot}

Pokémon Battle Revolution

Colosseum	Secondary Effect
Lagoon	{paralysis;STATUS;paralysis}
Main Street	{paralysis;STATUS;paralysis}
Neon	{paralysis;STATUS;paralysis}
Courtyard	{paralysis;STATUS;paralysis}
Gateway	lowers {Attack;STAT;ATTACK} by one stage.
Waterfall	{sleep;STATUS;sleep}
Sunny Park	{sleep;STATUS;sleep}
Crystal	lowers {accuracy;STAT;ACCURACY} by one stage.
Magma	lowers {accuracy;STAT;ACCURACY} by one stage.
Stargazer	lowers {accuracy;STAT;ACCURACY} by one stage.
Sunset	lowers {accuracy;STAT;ACCURACY} by one stage.

Gen 5

Terrain	Secondary Effect	Move Animation
Building and urban	{paralysis;STATUS;paralysis}	{Body Slam;MOVE;body-slam}
Sand, plain terrain, rock and link battle	lowers {accuracy;STAT;ACCURACY} by one stage.	{Mud Slap;MOVE;mud-slap}
Cave	{flinching;STATUS;flinch}	{Rock Throw;MOVE;rock-throw}
Grass	{sleep;STATUS;sleep}	{Needle Arm;MOVE;needle-arm}
Water	lowers {Attack;STAT;ATTACK} by one stage.	{Water Pulse;MOVE;water-pulse}
Puddles	lowers {Speed;STAT;SPEED} by one stage.	{Mud Shot;MOVE;mud-shot}
Snow	{freeze;STATUS;freeze}	{Avalanche;MOVE;avalanche}
Ice	{freeze;STATUS;freeze}	{Ice Shard;MOVE;ice-shard}

Gen 6

Terrain	Secondary Effect	Move Animation
Building, plain terrain, Sky Battles, and link battles	{paralysis;STATUS;paralysis}	{Body Slam;MOVE;body-slam}
On Electric Terrain	{paralysis;STATUS;paralysis}	Thunder Shock
Sand and rock	lowers {accuracy;STAT;ACCURACY} by one stage.	{Mud Slap;MOVE;mud-slap}
Cave	{flinching;STATUS;flinch}	{Rock Throw;MOVE;rock-throw}
Burial ground	{flinching;STATUS;flinch}	Shadow Sneak
Space	{flinching;STATUS;flinch}	Swift
Water and underwater	lowers {Attack;STAT;ATTACK} by one stage.	{Water Pulse;MOVE;water-pulse}
Swamp water and marsh	lowers {Speed;STAT;SPEED} by one stage.	{Mud Shot;MOVE;mud-shot}
Soaring in the sky and Sky Pillar	lowers {Speed;STAT;SPEED} by one stage.	Gust
Snow	{freeze;STATUS;freeze}	{Avalanche;MOVE;avalanche}
Ice	{freeze;STATUS;freeze}	{Ice Shard;MOVE;ice-shard}
Volcano	burn	Incinerate
Grass, Grassy Terrain, and Coumarine Gym	{sleep;STATUS;sleep}	{Needle Arm;MOVE;needle-arm}
On Misty Terrain	lowers Special Attack by one stage.	Fairy Wind

Gen 7

Terrain	Secondary Effect	Move Animation
Building, plain terrain, Sky Battles, and link battles	{paralysis;STATUS;paralysis}	Spit Up
On {Electric Terrain;MOVE;electric-terrain}	{paralysis;STATUS;paralysis}	{Thunder Shock;MOVE;thunder-shock}
Cave	{flinching;STATUS;flinch}	{Rock Throw;MOVE;rock-throw}
Sand, dirt and rock	lowers {accuracy;STAT;ACCURACY} by one stage.	{Mud Slap;MOVE;mud-slap}
Water	lowers {Attack;STAT;ATTACK} by one stage.	{Water Pulse;MOVE;water-pulse}
Snow and ice	{freeze;STATUS;freeze}	{Ice Shard;MOVE;ice-shard}
Volcano	{burn;STATUS;burn}	{Incinerate;MOVE;incinerate}
Ultra Space	lowers {Defense;STAT;DEFENSE} by one stage.	Psywave
Grass, field, flowers, and on {Grassy Terrain;MOVE;grassy-terrain}	{sleep;STATUS;sleep}	{Needle Arm;MOVE;needle-arm}
On {Misty Terrain;MOVE;misty-terrain}	lowers {Special Attack;STAT;SPATK} by one stage.	{Fairy Wind;MOVE;fairy-wind}
On Psychic Terrain	lowers {Speed;STAT;SPEED} by one stage.	Confusion

• In Gen 3-4 Secret Power's power is doubled by Serene Grace
• In Gen 3 and
  ORAS
  Secret Power can be used out of combat to create a Secret Base
• From Gen 8 onwards this move can not be selected in battle.