Cactuars are recurring creatures in the Final Fantasy series along with Chocobos and Moogles. They are little green cacti-men with arms and legs and some form of unusual expression on their faces. They first appeared in Final Fantasy VI.
Cactuars are generally "hit-and-run" enemies. They will sometimes attack unprovoked, though it usually takes an attack on one of them to retaliate with their signature move, "1,000 Needles," which does exactly 1,000 damage, regardless of the target's defense or stats. This attack is usually followed by a Flee move. Cactuars never stay in a battle for long, and even if they don't perform 1,000 Needles, they will flee. The challenge of fighting a Cactuar is most commonly derived from managing to defeat one before it is able to escape.
Final Fantasy VIII
Some Final Fantasy games have featured tweaks on the Cactuar concept. For example, Final Fantasy VIII features a Jumbo Cactuar, which is both an optional boss and optional Guardian Force summon. It has the move called "10,000 Needles," which is the upgraded "1,000 Needles." It does exactly 10,000 damage (basically a guaranteed kill on any party member) regardless of defense or stats.
Final Fantasy X-2
Final Fantasy X-2 also added to the Cactuar profile, saying that the Cactuars were actually children Cacti. There is a mini-game in which the player must help the Cacti from the Cactuar Nation find ten missing Cactuar children. The player must also fight and defeat a Jumbo Cactuar (much like in Final Fantasy VIII), and it's also an Oversoulable monster.
Final Fantasy XI
Final Fantasy XI featured the first major design change of the Cactuar since it's introduction in FFVI. It was designed to appear somewhat more lifelike. Also some appear with their Japanese name "Sabotender." Maintained were the cactus's signature high evasion, lightning quick attacks, and the "1,000 Needles" attack.
Lightning Returns: Final Fantasy XIII
In Lightning Returns: Final Fantasy XIII, Cactuars can be found roaming the Dead Dunes region. Like most other creature types found in the game, it can be driven to extinction if the player succeeds in killing enough of them in a single play-through. There is also a separate, unique Cactuar enemy called the Cactair; essentially, a Cactuar sporting an afro. Defeating the Cactair is a requirement to complete one of the game's main quests. Its behavior is unique, in that while it has only 200 hit points, no matter how powerful Lightning is, her individual strikes will only deal a single hit point of damage to it.
Mario Hoops 3-on-3
Cactuar appears in Mario Hoops 3 on 3 as an unlockable character alongside other Final Fantasy characters. Its signature shot is 1,000 Needles.