Delta Stream (デルタストリーム, Delta Stream?) is an Ability exclusive to Mega Rayquaza, introduced in Generation VI.
Effect
The Pokémon starts a mysterious air current when it enters battle. While the Pokémon is on the battlefield, this air current completely neutralizes the Flying-type's weakness to Rock, Ice, and Electric-type attacks, and prevents all other weather effects from occurring. Abilities like Primordial Sea and Snow Warning, for example, will fail while Delta Stream is active. In multi-battles, if an active Pokémon is pure Flying-type, that Pokémon will have no weaknesses, as long as the user of Delta Stream remains in play. This will affect Electric/Flying Pokémon as well, as Delta Stream does not lift their Ground-type immunity.
The effects of Delta Stream will dissipate once the user leaves the battle.
| Generations | Description |
|---|---|
| Generation VI | Affects weather and eliminates all of the Flying type's weaknesses. |
| Generation VII | The Pokémon changes the weather to eliminate all of the Flying type's weaknesses. |
Pokémon
| Pokémon | Type | First Ability | Second Ability | Hidden Ability | |
|---|---|---|---|---|---|
 | Mega Rayquaza |  Dragon /  Flying | Delta Stream | — | — |
| Generation III · Generation IV · Generation V · Generation VI · Generation VII · Generation VIII · Generation IX | |
| A | |
| B | |
| C | |
| D |
|
| F | |
| G | |
| M | |
| P | |
| R | |
| S | |
| T | |
| Pokémon X and Pokémon Y · Pokémon Omega Ruby and Pokémon Alpha Sapphire | |