I love the cactus men in Bas-Lag. The main conceit of the books is that there's a magical mutating force in the world that was unleashed thousands of years ago and warped humankind into various 'Xenians', possibly a result of the arrival of a race from another world. The force is called 'Torque' and it's used both as an analogue to nuclear weaponry and a symbol for conflict. Anyway, the Xenians take on many, many forms. There's the kephri who are sexually divided between females with human female bodies with a scarab body mounted on thier head, and males who are just large unintelligent bugs that mate with the females scarab heads. There's the Anophilii, mosquito people that once controlled an entire continent in the legendary 'Malarial Empire'. There's the Vodyanoi who spend most of thier time in water to preserve thier skin and can control and shape water as if it were clay.
And then there's the cactus men. The Cactacae. They're large humanoids with sap for blood and plant fibres for muscles. They're a bit more difficult to kill than humans, a bit more resistant to violence. There are exceptions, but most of the Cactacae in the books are large and loud, violent and swaggering, protected by thier vegetable anatomies. They're usually employed as navvies, as bodyguards and bouncers or as pirates where they use trained chimps to manipulate riggings thier large frames are too heavy to get to. Whenever someone swears in a Bas-Lag book there's a good chance it's a Cactacae.