You can bless some reference into a class without the class (package) being loaded.

my $demo = bless {}, 'I::Just::Made::This::Up';
print "Things in UNIVERSAL:: work.\n" if $demo->isa('I::Just::Made::Th
+is::Up');
$demo->opened();
__END__
Things in UNIVERSAL:: work.
Can't locate object method "opened" via package "I::Just::Made::This::
+Up"
[download]