If you know the index ($ix) of the element you want to move to the first position:

@array[0..$ix] = @array[$ix, 0..$ix-1]
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Otherwise, and if you are sure the array contains the given element:

my $element = 'dog';
my $last = $element;
for (@array) {
  ($_, $last) = ($last, $_);
  last if $last eq $element;
}
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