Answer:
It is probably the most laid-back member of the animal kingdom.
A mysterious, fantastic creature, It has one defining feature, And for humans at their worst, In their eyes it's just a horse
A nutcracker up in a tree
The ones in the sea are prickly, but the ones on the street might pickpocket you.
It's black and every time it speaks it says its name.
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.