ghost.rb

require 'fiddle/import'

class Object
  extend Fiddle::Importer

  RUBY_FL_SINGLETON = 1 << 12
  RBasic = struct ['uintptr_t flags', 'uintptr_t klass']

  private_constant :RUBY_FL_SINGLETON, :RBasic

  def ghost
    basic.flags |= RUBY_FL_SINGLETON
    true
  end

  def unghost
    basic.flags &= ~RUBY_FL_SINGLETON
    true
  end

private

  def ptr
    __id__ * 2
  end

  def basic
    RBasic.new ptr
  end
end