Delta Stream (Ability)

Delta Stream (Japanese: デルタストリーム Delta Stream) is an Ability introduced in Generation VI. It is the signature Ability of Mega.

In battle
When a Pokémon with Delta Stream enters the battle or a Pokémon gains the Ability, a unique weather condition called mysterious air current is created. In a Rotation Battle, Delta Stream will not activate if the Pokémon is sent out in a rotated-out position, nor will it activate when that Pokémon is rotated in. In addition, Delta Stream will not activate if a mysterious air current is already present on the battlefield or if the Pokémon's Ability is suppressed prior to it gaining Delta Stream.

A mysterious air current causes moves that would be super effective against pure Pokémon to instead deal neutral damage to all Flying-type Pokémon (unless a Pokémon on the field has the  or  Ability). Outside of Inverse Battles, this causes Electric-, Ice-, and moves to deal neutral damage to Flying-type Pokémon; during Inverse Battles, this causes Bug-, Fighting-, Grass-, and  moves to deal neutral damage to Flying-type Pokémon. If a move is not super effective against the Pokémon's other type (for dual-typed Pokémon), this no longer counts as a super-effective hit (for the purposes of, etc.). A mysterious air current has no effect on or.

Additionally, a mysterious air current causes the weather-modifying moves, , , and to fail if used; and causes the Abilities , , , and  to fail to activate.

Once in effect, as long as there is a Pokémon on the field with the Ability Delta Stream active (even if it is not the Pokémon who created it), the mysterious air current will remain in effect unless it is replaced. (If the only Pokémon on the field with Delta Stream is rotated out or switched out, or has its Ability suppressed or replaced, the mysterious air current will dissipate.) The mysterious air current can be replaced by or.

Outside of battle
Delta Stream has no effect outside of battle.

Description

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In the Pokémon Adventures manga

 * is revealed to have Delta Stream as its Ability when Mega Evolved.

In other languages
Delta-Wind Ráfaga delta Souffle Delta Flusso Delta デルタストリーム 德尔塔气流（特性）