Acid

Acid is a recurring enemy ability and Blue Magic spell. It often inflicts various Status Effectes when it deals damage to the opponent.

Final Fantasy VI
Acid is an enemy ability, found only in the Advance version and used by Abyss Worm, it inflicts Sap to one party member.

Crisis Core -Final Fantasy VII-
Acid is an enemy ability used by Bizarre Bug which deals physical, non-elemental damage as well as Poison.

Final Fantasy VIII
Acid is a Blue Magic spell learned by Quistis from the Mystery Fluid item obtained from the Gayla or its Triple Triad card via refining. Acid does non-elemental damage to one enemy and may add Vit 0, Poison, Petrify, and/or Darkness status effects. However, this all depends on the Crisis Level Quistis is in: The lower her HP when used, the higher the chance of using the highest Crisis Level version of the move.

The statistics of this spell is as follows per Crisis Level:
 * Crisis Level 1: Base power of 30, can inflict Poison.
 * Crisis Level 2: Base power of 38, can inflict Poison and Blind.
 * Crisis Level 3: Base power of 44, can inflict Poison, Blind, Silence, and Vit 0.
 * Crisis Level 4: Base power of 52, can inflicts Poison, Blind, Silence, Vit 0, and Petrify.

Final Fantasy Tactics Advance
Acid is learned from Flans and inflicts a random status ailment on the target, usually being either Disable or Stop. The spell costs 12 MP to cast.

Final Fantasy Tactics A2: Grimoire of the Rift
Acid is used by the Flan family and inflicts a random status ailment on the target. Blue Mages cannot learn this ability.

Final Fantasy Legend III
Acid is a physical attack that damages one enemy. Pentagon, Serpent, and Agron can use this attack.

Final Fantasy Crystal Chronicles: The Crystal Bearers
Acid is a monster ability the Bloodbones, Spitting out large quantities of Red Fluids causing heavy damage at a medium range.