Cactuar is an esper in Final Fantasy VI that can be acquired as magicite. It is one of four espers that were added to Game Boy Advance version of the game. The cactuar magicite can summon either a normal cactuar or the Gigantuar.
The cactuar esper is identical to regular cactuars fought as enemies. They are small bipedal cacti with stiff movements and their arms and legs held at sharp angles, and it has a simple face consisting of three holes for its eyes and mouth. It has three spines emerging from the top of its head. The Gigantuar retains this basic design but is much larger, and has a curled mustache.
The Gigantuar was one of several espers captured by the Gestahlian Empire during their first raid on the esper world. The captive espers were taken back to the Magitek Research Facility at Vector, and for sixteen years they were experimented on and had their magic drained to develop the Empire's Magitek army.
Shortly before the Returners infiltrated the facility, four espers including the Gigantuar escaped the Magitek Research Facility. After the apocalypse the Gigantuar prowled the desert near Maranda where cactuars were known to roam, frightening travellers with stories of a giant cactuar. The Returners went hunting for the Gigantuar and defeated it in battle, transforming it into magicite that they took.
The cactuar magicite costs 50 MP to summon. When summoned it will randomly spawn a cactuar that uses 1000 Needles on all enemies to deal a fixed 1,000 damage, or the Gigantuar that uses 10,000 Needles? on all enemies to deal a fixed 9,999 damage. Cactuar's magicite grants +2 Speed at level up.
The cactuar magicite is not terribly useful due to its random nature, and there are many other ways to deal 9,999 damage to all enemies, including Bahamut who can be acquired at the same time. However, it does have an advantage in that it costs much less MP to summon than other late-game espers. It is terrifically useful for its +2 Speed bonus, alleviating the need to hang on to the Odin magicite that was previously the only esper to provide a Speed bonus. With only a few levels with cactuar equipped to boost their Speed, the player may begin to notice a character's ATB gauge filling significantly faster in battle.
The Cactuar is most useful for teaching Hastega at a faster rate than Quetzalli, the only other way to learn Hastega. Its other spells are useful as utility spells but not terribly critical.
The Gigantuar must be defeated as a boss in the desert south of Maranda to receive the cactuar magicite. The party must first kill ten normal cactuar, after which they can encounter the Gigantuar as a random encounter.
Behind the scenes
The cactuar magicite and the Gigantuar are based on the cactuar Guardian Force from Final Fantasy VIII and the Jumbo Cactuar boss that yields the Guardian Force. The Gigantuar in Final Fantasy VI bears the same mustache the Jumbo Cactuar does in Final Fantasy VIII and is encountered in the same manner, a boss roaming a desert where normal cactuars appear. Its summon ability is also the same - the cactuar Guardian Force deals 1000 damage for each increment of ten in its level, up to 10,000 damage at level 1000.
The name "Cactuar" may be a portmanteau of "cactus" and "liar".