Sometimes it's fun to give any old object an obscure payload. AKA, a parasite.

parasite.rb

module Parasite

  def self.infect(object)
    (class << object; self end).class_eval do
      include Beasties
    end
  end

  module Beasties
    def __parasites__
      @__parasites__ ||= {}
    end

    def set_parasite(name, value)
      __parasites__[name] = value
    end

    def get_parasite(name)
      __parasites__[name]
    end
  end
end




if __FILE__ == $0
  x = "Hello world"
  y = "Hello world"

  Parasite::infect x

  puts x.respond_to? :set_parasite
  puts y.respond_to? :set_parasite

  x.set_parasite(:abc, 45)
  puts x.get_parasite(:abc).inspect

  Parasite::infect y
  puts y.get_parasite(:abc).inspect
  
end