Cactrot - The name of the cactus monster in Final Fantasy IIIus. (Not Final Fantasy 6 -- in the Japanese version his name appears to be "Sabotender". In all the games he's in, apparently.)
In FFIII he appears in the Maranda Desert. If you beat him, you get 10,000 GP and 10 AP (which is really helpful for mastering the Espers' spells). Sound tough? ... He's only got 3 HP. Of course he's next to impossible to hit with normal attacks, but if your characters have Sniper Sight you can beat him easy.
Watch out for his Blow Fish attack, which'll take off 1000 HP.