Method objects are created by Object#method, and are associated with a particular object (not just with a class). They may be used to invoke the method within the object, and as a block associated with an iterator. They may also be unbound from one object (creating an UnboundMethod) and bound to another.
class Thing def square(n) n*n end end thing = Thing.new meth = thing.method(:square) meth.call(9) #=> 81 [ 1, 2, 3 ].collect(&meth) #=> [1, 4, 9]