Be very careful with &foo;. This is a powerful, but dangerous way to call a function and should only be done when the special semantics are intended.

Powerful? Dangerous? Special semantics? This form of sub call will automagically grab the current @_ for its arguments. Combine that with Perl's pass by reference subroutines and serious weirdness may ensue.

See Messing with @_ for an example of how this can be used and/or abused.