Normally, I might get the metaclass for a particular instance of a Ruby object with something like this:

class C
  def metaclass
    class << self; self; end
  end
end

# This is this instance's metaclass.
C.new.metaclass => #<Class:#<C:0x01234567>>

# Successive invocations will have different metaclasses,
# since they're different instances.
C.new.metaclass => #<Class:#<C:0x01233...>>
C.new.metaclass => #<Class:#<C:0x01232...>>
C.new.metaclass => #<Class:#<C:0x01231...>>

Let's say I just want to know the metaclass of an arbitrary object instance obj of an arbitrary class, and I don't want to define a metaclass (or similar) method on the class of obj.

Is there a way to do that?