unbound_methods.rb

class Dog
  def initialize(name)
    @name = name
  end
  def to_s
    "#<Dog name=#{@name}>"
  end
  def bark
    "WOOF"
  end
end

Dog.instance_method(:bark).bind(Dog.new('milo')).call #=> "WOOF"

# how?? what??

unbound_bark_method = Dog.instance_method(:bark) #=> #<UnboundMethod: Dog#bark>
dog = Dog.new('Milo') #=> #<Dog name=Milo>
bark_method = unbound_bark_method.bind(dog) #=> #<Method: Dog#bark>
bark_method.receiver #=> #<Dog name=Milo>
bark_method.owner #=> Dog
bark_method.call #=> "WOOF"