why can't I collapse reference variables?

Hello, the following question I posted on perl.beginners but for a few
days there is no response, so maybe it is not a beginners question?
Nah, it must be :)

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If I can do this:

$ref = \@foobar;
print @$ref;

then why can't I do this:

print @\@foobar;
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I have this kind of problem often, let me give another example, I
think it is similar, let me know if not.

Why are all the printouts different:

@foobar = ();
print \@foobar;  #prints as reference to ARRAY

$foobar = \();
print $foobar;  # prints as reference to SCALAR

print \();  #prints as array of references to SCALAR, in this case
empty array