Acid Rain

Acid Rain (アシッドシャワー) is a recurring enemy ability in the series. It often inflicts non-elemental damage to the entire party, as well as inflicting Poison.

Final Fantasy
Acid Rain is only used by the Phantom Train in the GBA/PSP/iOS versions. It inflicts major non-elemental damage to the party.

Final Fantasy VI
Acid Rain is used by several enemies in the game, and it inflicts Poison and Water-elemental damage to the party as well as inflicting Sap. It has a power of 25 and a hit rate of 100.

Final Fantasy VII
Acid Rain is an enemy ability used by Epiolnis that inflicts Poison-elemental magic damage to the character with the highest HP. It has a power equal to 1.25x the enemy's Strength stat, dealing roughly around 645 damage.