class Nokogiri::XML::Document

... which does absolutely nothing.
irb> doc.slop!
... followed by irb's implicit inspect (and therefore instantiation of every node) ...
irb> doc = Nokogiri::HTML my_markup

and not

irb> doc = Nokogiri::Slop my_markup

irb, the preferred idiom is:
is called will not be decorated with sloppy behavior. So, if you're in
Note that any nodes that have been instantiated before #slop!

Explore a document with shortcut methods. See Nokogiri::Slop for details.
#

def slop!
  unless decorators(XML::Node).include?(Nokogiri::Decorators::Slop)
    decorators(XML::Node) << Nokogiri::Decorators::Slop
    decorate!
  end
  self
end