ElementProxy undefs a bunch of standard methods on objects:

# Remove all instance methods so even things like class()
# get handled by method_missing(). <lifted from activerecord>
instance_methods.each do |m|
  unless m.to_s =~ /^(?:nil\?|send|object_id|to_a|tap)$|^__|^respond_to/
    undef_method m
  end
end

This undefing is too severe and can cause issues when methods common to most objects are not available. #123 describes an issue with RSpec expectations. Additionally, inspecting instances of ElementProxy in debuggers like Rubymine can sometimes crash the debugger.

Reimplement the proxy code in ElementProxy to be less severe.

Some ideas:

1. Use SimpleDelegator.
2. Don't undef any methods.