Ugh. :-( Sorry, but I'm not going to be sticking stuff in UNIVERSAL:: willy nilly, particularly not to fix such a trivial complaint. You could put it in a different package and call it as in ->UTIL::invoke_methods() or something.

In terms of parameter format, your code is quite similar to my first attempt at multiple method calls against the same object (f.ex GUI programming). Putting the method name outside the list of parameters but it's awkward rather than convenient in practice. In my code I did it because I wanted to be able to represent sub-callchains as in

$obj->foo;
$obj->child->bar;
$obj->baz;
[download]

but it's still too limited anyway because you can't pass parameters to intermediate methods. Putting the methodname inside the arrayref actually allows for syntax to handle this. (You put nested arrayrefs in front of the name of the method to call, easily distinguished because the name must be a string.)

Another option might be something like

sub CHAIN::AUTOLOAD {
    my $self = shift;
    my ( $method ) = ( our $AUTOLOAD =~ /.*::(.*)/ );
    $self->$method( @_ );
    $self;
}

# now we can say

my $window = Gtk2::Window
    ->new( "toplevel" )
    ->CHAIN::signal_connect( delete_event => sub { Gtk2->main_quit } )
    ->CHAIN::set_title( "Test" )
    ->CHAIN::set_border_width( 15 ),
    ->CHAIN::add( Gtk2::Button
        ->new( "Quit" )
        ->CHAIN::signal_connect( clicked => sub { Gtk2->main_quit } )
    )
    ->CHAIN::show_all();
[download]

but again, ugh.

Trust me, I've been around the block a number of times with this one. All of the “solutions” suck, the one in the root node just IMHO sucks a little less than all the others. We need Perl6.

Update: oh, and thanks for the heads up on $@!

Makeshifts last the longest.