Fog (ability)

Fog is a recurring spell and status ailment caused by said spell in some installments.

Final Fantasy II
Fog is a White Magic spell which causes the Amnesia status on one or all targets, and is Mind-elemental. As with all spells, its success rate increases with every successive spell level. Any character can learn Fog by having them use the Fog Tome (called the Fog Scroll in the Origins release). The Rune Axe casts Fog when used as an item.

Final Fantasy XII
Fog is an enemy exclusive spell which drops the target's MP to zero. Another two enemy exclusive spells, Fear and Fearga, also have the effect reduce MP, albeit partially.

Final Fantasy XIII
Fog is a Saboteur's spell which deals minor magical damage and seals all magic abilities to one enemy. It is classified as a debilitation spell. An upgraded version is called Fogga, which has an area of effect to the opponent side.

Fog can be learned by various characters at different Crystarium Stages:
 * Sazh Katzroy on Stage 9.
 * Snow Villiers on Stage 7.
 * Oerba Dia Vanille on Stage 8.
 * Oerba Yun Fang on Stage 7.

Final Fantasy XIII-2
Fog reappears as a Saboteur spell, which, aside from dealing minor magical damage and disabling the target's magic abilities, can also reduce the target's maximum HP due to the applied Wound damage. It is a monster ally exclusive ability, best infused using a level 20 Viking.

Final Fantasy Legend II
There's a spellbooks called Fog and it has a book icon before its name. It can be bought in numerous towns across the various worlds for 6800 GP. It only has 30 uses, and also increases a Robot's HP by 45 when equipped on them. The damage formula for Fog is the user's Mana x10, deals Poison-elemental damage to one group of enemies.