Can I invoke an instance method on a Ruby module without including it?

I think the shortest way to do just throw-away single call (without altering existing modules or creating new ones) would be as follows:

Class.new.extend(UsefulThings).get_file

If a method on a module is turned into a module function you can simply call it off of Mods as if it had been declared as

module Mods
  def self.foo
     puts "Mods.foo(self)"
  end
end

The module_function approach below will avoid breaking any classes which include all of Mods.

module Mods
  def foo
    puts "Mods.foo"
  end
end

class Includer
  include Mods
end

Includer.new.foo

Mods.module_eval do
  module_function(:foo)
  public :foo
end

Includer.new.foo # this would break without public :foo above

class Thing
  def bar
    Mods.foo
  end
end

Thing.new.bar  

However, I'm curious why a set of unrelated functions are all contained within the same module in the first place?

Edited to show that includes still work if public :foo is called after module_function :foo